The 1900 Census was the first in which an advance census report was mailed to households on a nationwide basis so that written information for household members would he available when the enumerator called. This advance report contained instructions as to who was to be included; and, since it was available prior to the enumerator's visit, it permitted the members of the household to develop a correct list of persons to be enumerated in the housing unit, It also served to focus attention on questions relating to coverage during the interview conducted by the enumerator, Not all householders filled out the advance report; but many did, and the net effect of the whole procedure was to add to the enumeration situation another factor calculated to increase the completeness of enumeration above that achieved in previous censuses.

In addition to the regular census schedule, the enumerator carried a listing book in which he recorded the address, name of head, and number of persons, as he systematically canvassed his district. Since this information was recorded at his first visit (regardless of whether or not anyone was at home), a basic record was established which permitted an adequate control over callbacks and provided a convenient basis for subsequent checking of the enumerator's work. This procedure was designed to reduce losses incident to the failure to make callbacks and to aid in the overall quality control in the enumeration.

In areas covering approximately 82 percent of the total 1960 population, the 1960 Census was conducted in two stages. In the first stage, the enumerator visited each household in his enumeration district and collected the relatively small amount of information - name, household relationship, sex, race, birth date, and marital status - which, along with some limited housing information, was obtained on a complete-count basis. He left a sample schedule with additional questions at every fourth household, with the request that it be filled out and mailed to the census office. This procedure meant that the first-stage enumerator needed training only on the relatively few 100-percent items; and, therefore, relatively more emphasis could be placed on coverage in his training. Likewise, in the actual canvass, more attention could be given to coverage and the canvass could be completed more rapidly. That this acceleration was achieved is indicated by the fact that in 1960 about 85 percent of the enumeration was completed by April 15, whereas in 1950 the comparable figure was about 67 percent. The concentration of the canvass into a shorter period of time should have reduced the number of movers who were missed altogether or were counted twice.
In sparsely settled parts of the country, the ratio of travel time to enumeration time was so great as to make it impractical to carry out the two-stage procedure. Hence, the traditional one-stage procedure was used and both complete-count and sample data were collected in a single visit.

The enumeration was carried out under the immediate supervision of crew leaders. Crew leaders generally supervised from 15 to 20 enumerators and were assisted by a field reviewer. In previous censuses, the crew leader had general responsibility for reviewing his enumerator's work, but in the 1900 Census this responsibility was formalized in a systematic quality control procedure and the crew leader was provided with the assistance of a field reviewer. Prior to the beginning of enumeration, the crew leader was instructed to list the first 15 to 25 housing units in each enumeration district (the area assigned to one enumerator) and an additional 10 scattered throughout the area to be covered by the enumerator. Ho was then instructed to review the work of each enumerator within the first day or two of enumeration. This review was made on the basis of a standard form, which permitted the development of a score for evaluating the enumerator's work and this initial review included a check of the enumerator's listing against the crew leader's prelisting. On the basis of this initial- review score, the crew leader could determine whether the enumerator should be permitted to complete his enumeration district with only a final review, whether the enumerator needed additional training and further reviews in the course of his work, or whether the services of the enumerator might bo dispensed with. It was hoped that this formalized procedure would lead to earlier correction of erroneous practices and to the early dismissal of inept enumerators who, according to previous studies, would otherwise contribute a very large number of errors.

One of the major difficulties encountered in any canvass is the difficulty of finding respondents at home. In some areas there are many households where, even after repeated visits, the enumerator falls to find anyone at home, The effect of these repeated visits, or "callbacks" is, of course, to reduce the enumerator's effective hourly rate of pay (since he was paid on a piece-rate basis), and to postpone the completion of his canvass. As a compromise between these administrative considerations and considerations of complete coverage, a "close out" procedure was used. If no one was home on his first visit, the enumerator was instructed to make two callbacks, and if on the second callback he still found no one at home, his instruction was to obtain and record whatever Information he could obtain from neighbors and close out the case. In such cases he was to leave a note at the household informing them that he had enumerated a staled number of persons at the household and asking that the census office be notified if this was incorrect.

In order to prevent the misuse of this close-out procedure, the quality control system provided for a final review of the listing books and those which showed evidence of excessive use of the close-out procedure at the expense of coverage were returned to the field for additional checking.

In the dozen or so large cities in which enumeration had been especially difficult and in which there was an indication that the totals might well fall below the 1950 totals, the general system of quality control was amplified. Listing books were reviewed to determine whether or not there were excessive numbers of vacancies, households with no occupants, or households with one occupant. In all of the enumeration districts where any of these numbers were excessive a field check of the enumeration was made and, if necessary, the enumeration district was completely re-enumerated. This procedure was intended to improve coverage, particularly in those areas of large cities where it is difficult to find people at home.

Finally, in the edit of the complete-count population data on the computer, housing units which according to the housing information were occupied, but for which no population was recorded, were identified, and persons living in neighboring housing units were imputed to the housing unit in question. The procedure added approximately 0.4 percent to the population enumerated.

In addition to the novel procedures developed for the 1900 Census, there were a number of other standard practices in this field developed in earlier censuses which were used in 1960. Among these may be mentioned the intensive and systematic training of enumerators, providing enumerators with maps of their enumeration districts, special enumeration of places occupied by transients and a check of the forms obtained from transients against the schedule for their usual place of residence, the publication of "missed persons" forms in local newspapers, and finally the preliminary announcements of population totals by district supervisor for the consideration of local officials and the identification and resolution of problems appearing to involve underenumeration.

As a supplement to this local consideration given preliminary figures, district supervisors were requested to wire the preliminary counts for counties and large cities to the Bureau. These telegraphic reports were cheeked against available data for the areas in question and explanations of unlikely results were requested from the district supervisors. This procedure then provided insurance against the possibility that there had been gross errors in the preliminary counts.

Although there is great interest in the degree of underenumeration in the census, the problem of measuring it is a difficult one, since it involves the development of a standard for comparison which is necessarily hypothetical. Empirical standards which have been used are, like the census, subject to error, and, therefore, it is never certain what part of the difference observed between the standard and the census is attributable to errors in the census, and what part is attributable to errors in the standard. For example, the Post-Enumeration Survey of 1950 indicated a net underenumeration of 1.4 percent, a difference presumably attributable to the greater dedication and skill of the enumerators in that survey. On the basis of an independent demographic analysis, however, it seems likely that the true net underenumeration was closer to 3 percent and that the enumeration of the Post-Enumeration Survey had some of the same kinds of limitations as those of the decennial census, although in a lesser degree.

One method of estimating the comparative completeness of successive censuses involves the use of vital statistics and statistics of immigration and emigration in conjunction with the data of successive censuses. Since the population at a given census should represent the population at the previous census plus births and immigration minus deaths and emigration in the intervening period, it is possible, given the necessary statistics, to calculate the expected population on a given census date and to compare it with the enumerated population. If this comparison shows that the expected population exceeds the enumerated population, it may be inferred that the amount of underenumeration in the current census exceeded that in the previous census; if, on the other hand, the enumerated population exceeds the expected population, the inference is that the current census is the more complete one. These inferences, of course, rest on the assumption that errors in the measurement of births, deaths, immigration, and emigration are small in relation to the amounts of comparative underenumeration.

Preliminary investigation of the coverage of the 1960 Census from this point of view suggests that the level of underenumeration in that year was not essentially different from the corresponding level of 1950. This investigation will, of course, continue, but the efforts to measure underenumeration are by no means limited to this approach. The Bureau of the Census conducted its first Post-Enumeration Survey after the 1950 Census. A more intensive program of evaluation using a wide variety of approaches to the problem is being carried out for the 1960 Census, and the results of these studies will be published when they are completed.

The population of the United States on April 1, 1960, was 179,323,175; this figure represents an increase of nearly 28 million, or 18.5 percent, over the corresponding figure for April 1, 1950 (table 2). In absolute numbers this increase is greater than the increase during any previous intercensal period. In relative terms, the increase between 1950 and 1960 was the largest increase since the decade 1900 to 1910. It falls considerably short, however, of any of the decennial rates of increase which occurred during the nineteenth century.

The population of conterminous United States, that is, the United States excluding the newly admitted States of Alaska and Hawaii, was 178,464,236 on April 1, 1960. This figure represents an increase of about 27.8 million, or 18.4 percent, over the corresponding 1950 figure.

An examination of the decennial rates of increase since 1790 indicates that during each of the seven decades up to 1860 the population increased by approximately one-third. On the basis of an estimated correction made for the apparent underenumeration in 1870, the percentage increases for the decades 1860 to 1870 and 1870 to 1880 become, respectively, 26.6 and 26.0 rather than 22.6 and 30.1. (See footnote 3 of table 2.) On the basis of these revised figures, the decennial rates of increase for the period 1860 to 1890 were all in the neighborhood of 25 percent.² The decennial rates of increase in the period 1890 to 1910 were about 20 percent, and those for the period 1910 to 1930, about 15 percent. The percentage increase for the period 1930 to 1940, the decade of the depression, represents an all-time low.

The "center of population" is defined by the Bureau of the Census as that point which may be considered as the center of population gravity of the United States; in other words, the point upon which the United States would balance, if it were a rigid plane, without weight and the population were distributed thereon with each individual being assumed to have equal weight and to exert an influence on a central point proportional to his distance from that point. Table B and figure 10 give the approximate location of the center of population for conterminous United States at each census from 1790 to 1960.

Table B. Center of Population: 1790to 1960

Census year	North latitude			West longitude			Approximate location
United States	°	'	"	°	'	"
1960	38	35	58	89	12	35	In Clinton County, Ill., 6 1/2 miles northwest
1950	38	48	15	88	22	8	3 miles northeast of Louisville, Clay County. Ill.
Conterminous United States
1960	38	37	57	88	52	23	4 miles east of Salom, Marion County, Ill.
1950	38	50	21	88	9	33	8 miles north-northwest of Olney, Richland County, Ill.
1940	38	56	54	87	22	35	2 miles southeast by east of Carlisle, Haddon township, Sullivan County, Ind.
1930	39	3	45	87	8	6	3 miles northeast of Linton, Greene County, Ind.
1920	39	10	21	86	43	15	8 miles south-southeast of Spencer, Owen County, Ind.
1910	39	10	12	86	32	20	In the city of Bloomington, Ind.
1900	39	9	36	85	48	54	6 miles southeast of Columbus, Ind.
1890	39	11	56	85	32	53	20 miles east of Columbus, Ind.
1880	39	4	8	84	39	40	8 miles west by south of Cincinnati, Ohio (in Kentucky)
1870	39	12	0	83	35	42	48 miles east by north of Cincinnati, Ohio
1860	39	0	24	82	48	48	20 miles south by east of Chillicothe, Ohio
1850	38	59	0	81	19	0	23 miles southeast of Parkersburg, W. Va 1
1840	39	2	0	80	18	0	16 miles south of Clarksburg, W. Va 1
1830	38	57	54	79	16	54	19 miles west-southwest of Moorefield, W. Va.1
1820	39	5	42	78	33	0	16 miles east of Moorefield, W. Va.1
1810	39	11	30	77	37	12	40 miles northwest by west of Washington, D.C. (In Virginia)
1800	39	16	6	76	56	30	18 miles west of Baltimore, Md.
1790	39	16	30	76	11	12	23 miles east of Baltimore, Md.

¹West Virginia was set off from Virginia Dec. 31, 1862, and admitted as a State June 19, 1863.

The center of population of the United States moved westward within the State of Illinois between 1950 and 1960. The 1900 center of population is located about 50 miles east of East St, Louis and about miles northwest of Centralia, in Meridian Township, Clinton County, Ill. The 1960 center is located at latitude 38°35'58" North and longitude 89°12'35" West.

The new center of the United States is 10% miles south and 57 miles west of the 1950 center of the then 48 States, which was located near Olney, Richland County, Ill. Approximately 2 miles of the southward movement and 18 miles of the westward movement is due to the addition of Alaska and Hawaii as States. The remainder of the change resulted from shifts in the population of the 48 States. This westward movement of the center of population between 1950 and 1960 is the greatest during the present century and exceeds all movements westward since the decade of 1880 to 1890. The longest movement westward was during the decade from 1850 to 1860 when the center advanced 80,6 miles. The shortest movement westward was during the decade from 1910 to 1920 when it advanced only 9.8 miles. The point farthest north was the 1790 location, and the point farthest south, the 1960 location; but the difference is only 47 miles. The total westward movement from 1790 to 1960 was 701 miles.

The position of the "center of area," that is, the point on which the surface of the United States would balance if it were a plane of uniform weight per unit of area, is located in Butte County, South Dakota (approximate latitude 44°58' North, longitude 103°46' West).

The gross area, land and water, of the United States and its outlying areas at the time of the 1960 Census was 3,628,150 square miles (table 1). Puerto Rico and the outlying areas had an area of 12,939 square miles and constituted less than 0.4 percent of the aggregate area.

The area in 1790 was 888,811 square miles, or somewhat less than one-fourth of the present area, and embraced substantially all the territory between Canada and Florida and between the Atlantic Ocean and the Mississippi River, together with part of the drainage basin of the Red River of the North. This original territory and the successive major accessions of territory from 1790 to 1920 are shown in figure 3. In 1803, the area of the country was nearly doubled by the Louisiana Purchase; and, between 1840 and 1850, three large accessions of territory resulted in further increases aggregating 1,204,741 square miles, equivalent to two-thirds of the former area.

Table C. Territory of the United States And Its Outlying Areas: 1790 To 1960
[Gross area (land and water) in thousands of square miles]

Year	Total	States1	Other2
1960	3,628	3,615	13
1950	3,628	3,022	606
1940	3,735	3,022	713
1930	3,735	3,022	713
1920	3,735	3,022	713
1910	3,735	2,787	948
1900	3,735	2,717	1,018
1890	3,600	2,632	977
1880	3,600	2,087	1,521
1870	3,609	1,983	1,626
1860	3,022	1,713	1,309
1850	2,998	1,582	1,461
1840	1,788	935	853
1830	1,788	821	967
1820	1,788	754	1,034
1810	1,716	514	1,202
1800	880	526	363
1790	880	517	372

¹For the most part, the 1960 area of each State was used in computing the area included in the States at each decade. Minor adjustments in State boundaries were ignored, but major changes, such as the decreases in the area of Georgia prior to 1800 and 1810 when parts of the original area of the State were ceded to the Federal Government, are reflected in the figures.
²Includes the Commonwealth of Puerto Rico, the Territories prior to becoming States, and outlying areas of sovereignty or jurisdiction.

Source: U.S. Department of Commerce, Bureau of the Census, Historical Statistics of the United States, Colonial Times to 1957, Washington, D.C., 1960, Series Jl-2, and records of the Bureau of the Census.

For the United States, the population per square mile of land area in 1960 was 50.5 (table 2). For conterminous United States, that is, the United States excluding Hawaii and Alaska, the figure for 1960 was 60.1 as compared with 50.7 for the same area in 1950. Beginning with the Census of 1790, in which the population per square mile was 4.5, the figures at each subsequent, census have shown an increase in density with the exception of those for the Censuses of 1810 and 1850. In each of these years, the density was lower than it had been in the immediately preceding census because of large accessions of sparsely populated territory in the preceding decade.

Land includes dry land and land temporarily or partially covered by water, such as marshland, swamps, and river flood plains; streams, sloughs, estuaries, and canals less than one-eighth of a statute mile in width; and lakes, reservoirs, and ponds having less than 40 acres of area. The presentation of area measurements may be for total or gross area, including land and inland water.

The land area figures of incorporated places generally were supplied by city engineers. The definition of land as employed by the Bureau may not have been observed by those outside the Bureau, but the reasonableness of their measurements were reviewed before inclusion in the publications. Other area figures were supplied by government officials or other well informed sources, or were obtained by planimeter measurements of the best available maps.
Changes in areas from previous dates result from changes in boundaries and from re-measurements based on more accurate information. Transfers between land and water areas occur through construction of dams and reservoirs or the filling in of water area.

According to the definition adopted for use in the 1960 Census, the urban population comprises all persons living in (a) places of 2,500 inhabitants or more incorporated as cities, boroughs., villages, and towns (except towns in New England, New York, and Wisconsin) ; (6) the densely settled urban fringe, whether incorporated or unincorporated, of urbanized areas (see section below) ; (c) towns in New England and townships in New Jersey and Pennsylvania which contain no incorporated municipalities as subdivisions and have either 25,000 inhabitants or more or a population of 2,500 to 25,000 and a density of 1,500 persons or more per square mile; (d) counties in States other than the New England States, New Jersey, and Pennsylvania that have no incorporated municipalities within their boundaries and have a density of 1,500 persons per square mile; and (e) unincorporated places of 2,500 inhabitants or more. In other words, the urban population comprises all persons living in urbanized areas and in places of 2,500 Inhabitants or more outside urbanized areas (see the section "Places"). The population not classified as urban constitutes the rural population.

This definition of urban is substantially the same as that used in 1950; the major difference between 1950 and 1960 is the designation in 1960 of urban towns in New England and of urban townships in New Jersey and Pennsylvania. The effect on population classification arising from this change was actually small because, in 1950, most of the population living in such places was classified as urban by virtue of residence in an urbanized area or in an unincorporated urban place. (See sections below.) In censuses prior to 1950, the urban population comprised all persons living in incorporated places of 2,500 inhabitants or more and areas (usually minor civil divisions) classified as urban under somewhat different special rules relating to population size and density.²
The most important component of the urban territory in both definitions is the group of incorporated places having 2,500 inhabitants or more. A definition of urban territory restricted to such places, however, excludes a number of equally large and densely settled places merely because they are not incorporated places. Under the definition used previous to 1950, an effort was made to avoid some of the more obvious omissions by the Inclusion of selected places which were classified as urban under special rules. Even with these rules, however, many large and closely built-up places were excluded from the urban territory.
To improve its measure of the urban population, the Bureau of the Census adopted, in 1960, the concept of the urbanized area (see the section "Urbanized areas") and defined the larger unincorporated places as urban. All the population residing in urban-fringe areas and in unincorporated places of 2,500 or more is classified as urban according to the current definition. The urban towns, townships, and counties as defined for the 1960 Census are somewhat similar in concept to the minor civil divisions classified as urban under special rules in 1940 and 1930.

For the convenience of those interested in the historical trend of the urban and rural population, the 1950 and 1960 population figures are shown on the basis of both the "current" definition and the "previous" definition. Although the Bureau of the Census has employed other definitions of "urban" in prior years, the urban and rural population figures published here as according to the "previous" definition have been revised to present a substantially consistent series.
The 1950 figures on the population by urban-rural residence according to the "previous" definition have been revised since the publication of the 1950 reports. In the 1950 reports, the areas urban under the special rules of 1940 were those which had been so classified in 1940. Some of these areas no longer qualified as urban, whereas others which qualified in 1950 were not included. Prior to the 1960 Census, the list was revised to reflect this situation. As a result, the number of areas urban under the 1940 special rules in 1950 was increased from 140 to 175.

Under the current urban definition, 125,268,750 persons, or 69.9 percent of the population of the United States, were classified as urban in 1960. The remaining 54,054,425 persons constituted the rural population. The urban population according to the previous definition was 113,056,353, and the rural population was 66,266,822 (table 3).
The 1960 urban population according to the current definition consisted of the following: (a) The 106,308,257 inhabitants of the 4,699 incorporated places of 2,500 inhabitants or more; (b) the 5,106,083 inhabitants of the 620 unincorporated places of 2,500 Inhabitants or more; (c) the 3,313,559 residents of the 125 urban towns and townships and 1 urban county; and (d) the 10,540,851 persons living in urban-fringe areas outside urban places. Had the definition of 1940 been in effect, the urban population would have been the 106,308,257 inhabitants of the 4,699 incorporated places of 2,500 inhabitants or more and the 6,748,096 persons living in the 324 areas classified as urban under the special rules of 1940 (table D).

Table D. Population, Urban and Rural, According to Current and Previous Urban Definitions: 1960
[For description of current and previous definitions, see text]

Type of area and class of place in accordance with current urban definition	Total	Type of area and class of place in accordance with previous urban definition
		Urban			Rural
		Total	Incorporated urban places	Areas urban under special rule
Total	179,323,175	113,056,353	105,308,257	6,748,096	66,266,822
Urban, total	125,268,750	112,548,416	106,308,257	6,240,159	12,720,334
Within urbanized areas	95,848,487	85,115,137	79,487,607	5,627,530	10,733,350
Incorporated places of 2,500 or more	79,487,607	79,487,607	79,487,607	…	…
Incorporated places under 2,500	689,746	…	…	…	689,746
Urban towns or townships	3,140,537	2,975,085	…	2,975,085	165,452
Unincorporated places	2,679,492	616,630	…	616,630	2,062,862
Other urban territory	9,851,105	2,035,815	…	2,035,815	7,815,290
Outside urbanized places	29,420,263	27,433,279	26,820,650	612,629	1,986,984
Incorporated places of 2,500 or more	26,820,650	26,820,650	26,820,650	…	…
Unincorporated places of 2,500 or more	2,428,591	513,466	…	513,466	1,913,125
Urban towns or townships	178,022	99,163	…	99,163	73,859
Rural, total	54,054,425	507,937	…	507,937	53,546,488

Table 4 presents the population of the areas which, in 1900 and 1950, were urban under the special rules of 1940 and the classification of the 1960 population of the 1960 areas by urban and rural residence in accordance with the current urban definition. As shown in this table, 6,240,159 persons living in these areas in 1960 were classified as urban according to the current definition, and the remaining 507,937 were classified as rural. Of those classified as urban, 5,627,530 were urban by virtue of residence in unincorporated territory included in urban-fringe areas, 513,466 by virtue of residence in unincorporated places of 2,500 inhabitants or more outside urbanized areas, and 99,163 by virtue of residence in urban towns or townships outside urbanized areas (table D).

Included in the urban population in 1960 according to the current definition, but who would have been included in the rural population according to the previous definition, were. 10,733,350 persons living outside incorporated places of 2,500 in urban-fringe areas, 1,913,125 persons living in unincorporated places of 2,500 inhabitants or more outside urbanized areas, and 73,859 persons in urban towns or townships outside urbanized areas. On the other hand, 507,937 persons living in areas urban under special rules according to the previous definition were classified as rural according to the current definition. The net difference in the urban population which resulted from the change in definition, therefore, is 12,212,397, or 6.8 percent of the total population of the United States. In terms of the population classified in accordance with the previous urban definition, the change in definition resulted in an increase of 10.8 percent in the urban population and a decrease of 18.4 percent in the rural population (table 19).

The population of the incorporated places of 2,500 inhabitants or more constituted 84.9 percent of the urban population under the new definition and 94.0 percent of the urban population under the previous definition. The population living In other territory in the urban-fringe areas accounted for 13.1 percent of the urban population under the current definition, and outside urbanized areas the population in unincorporated places of 2,500 inhabitants or more accounted for 1.0 percent, and the population of urban towns and townships accounted for 0.1 percent.

Trends in urban and rural population, 1790 to 1960, between 1950 and 1960, the population classified as urban according to the current definition increased from 06,846,817 to 125,268,750, whereas the rural population declined slightly from 54,478,981 to 54,054,425. The Increase in the urban population was at the rate of 29.3 percent in contrast; to the decline of 0.8 percent for the rural population. As a result, the proportion of the population urban increased from 64.0 to 69.9 percent.

Historical trends in the urban and rural population can be examined only on the basis of the previous definition. On this basis, the urban population increased from 00,128,104 in 1050 to 113,056,353 in 1960, and the rural population from 61,197,604 in 1950 to 66,266,822 in 1960 (table 3). The gains of 22,028,159 in the urban, and 5,069,218 in the rural, population represented Increases of 25.4 and 8.3 percent, respectively. The numerical gain in the urban population was the largest in history and marked the eighth consecutive decade in which the numerical increase in the urban population exceeded that in the rural population.
In 1790, only 1 out of every 20 of the 3,929,214 inhabitants of the United States was living in urban territory (table 20). In every decade thereafter, with the exception of that from 1810 to 1820, the rate of growth of the urban population exceeded that of the rural population. By 1860, 1 out of 5 persons was Included in the urban population. The process of urbanization continued in the following decades, and by 1920 the urban population had exceeded the rural population. In 1960, about 5 out of every 8 persons were living in urban territory, according to the previous definition.

Population density by size of place in 1960, the urban population which constituted nearly 70 percent of the total population was concentrated in slightly more than 1 percent of the land area of the country (table E). The population of urbanized areas, something more than one-half of the total, occupied less than 1 percent of the total land area. Among urban places, the number of inhabitants per square mile decreased as size of place decreased. For places of 1,000,000 Inhabitants or more, the average density was 13,865 persons per square mile; for places between 100,000 and 1,000,000, average densities ranged between 4,000 and 6,000 per square mile, and the average density for places of 2,500 to 5,000 was 1,446. In urban-fringe areas outside urban places, the average density was 1,781 per square mile, and in rural territory the density was 15.

Table E. Population and Density in Groups of Places Classified According to Size: 1960

Area	Population	Land area in square miles	Population per square mile of land area
United States	179,323,175	3,548,974	51
Places of 1,000,000 or more	17,484,050	1,261	13,865
Places of 500,000 to 1,000,000	11,110,991	1,888	5,885
Places of 250,000 to 500,000	10,765,881	2,401	4,484
Places of 100,000 to 260,000	11,652,426	2,728	4,271
Places of 50,000 to 100,000	13,835,902	3,530	3,910
Places of 25,000 to 50,000	14,950,612	5,310	2,811
Places of 10,000 to 25,000	17,568,280	6,939	2,532
Places of 5,000 to 10,000	9,779,714	5,005	1,954
Places of 2,500 to 5,000	7,580,028	5,242	1,446
Other urban territory	10,540,851	5,917	1,781
Rural territory	54,054,425	3,508,736	15
Within urbanized areas	95,848,487	25,544	3,752
Places of 1,000,000 or more	17,484,050	1,261	13,865
Places of 500,000 to 1,000,000	11,110,991	1,888	5,885
Places of 250,000 to 500,000	10,765,881	2,401	4,484
Places of 100,000 to 260,000	11,652,426	2,728	4,271
Places of 50,000 to 100,000	13,835,902	3,530	3,910
Places of 25,000 to 50,000	8,0105,421	2,594	3,090
Places of 10,000 to 25,000	8,330,638	2,878	2,900
Places of 5,000 to 10,000	2,862,099	1,488	1,923
Places of 2,500 to 5,000	1,250,219	850	1,461
Other urban territory	10,540,851	5,917	1,781
Outside urbanized areas	83,474,688	3,523,430	24
Places of 25,000 to 50,000	6,935,191	2,725	2,545
Places of 10,000 to 25,000	9,287,048	4,066	2,272
Places of 5,000 to 10,000	6,917,615	3,517	1,967
Places of 2,500 to 5,000	6,320,809	4,386	1,448
Rural territory	64,054,425	3,508,786	15

The primary reason for the establishment of the decennial census of population, as set forth in the Constitution, was to provide a basis for the apportionment of members of the House of Representatives among the several States. Such an apportionment has been made on the basis of every census from 1790 to 1960, except that of 1920. Prior to 1870, the population basis for apportionment was the total free population of the States, omitting Indians not taxed, plus three- fifths of the number of slaves. After the apportionment of 1860 the fractional count of the number of slaves, of course, disappeared from the procedure; and in 1940 it was determined that there were no longer any Indians who should be classed as "not taxed" under the terms of the apportionment laws. The 1940 and 1950 apportionments, therefore, were made on the basis of the entire population of the 48 States, and that of 1960 on the basis of the entire population of the 50 States. All apportionments are made under the constitutional provision that each State should have at least one Representative, no matter how small its population.

The population base for apportionment and other significant items are shown in table F. The results of each apportionment, starting with the initial apportionment in 1789 and including those based on each census from 1790 to 1960, are shown by regions, divisions, and States in table 13.

Table F. Population Base for Apportionment and the Number of Representatives Apportioned: 1790 to 1960

Census year	Population base 1	Number of Representatives2	Ratio of apportionment population to Representatives	Date of apportionment act
1960	178,659,217	435	410,481	Nov. 15, 1941
1950	149,805,183	435	344,587	Nov. 15, 1941
1940	131,000,184	435	301,164	Nov. 15, 1941
1930	122,093,455	435	280,675	June 18, 1929
1920	(2)	435	(3)	(3)
1910	91,603,772	435	210,583	Aug. 8, 1911
1900	74,562,608	386	193,167	Jan. 16, 1901
1890	61,908,906	356	173,901	Feb. 7, 1891
1880	49,371,940	325	151,912	Feb. 25, 1882
1870	38,115,641	202	130,533	Feb. 2, 18724
1860	29,550,038	241	122,614	May 23, 18505
1850	21,766,691	234	93,020	May 23, 18506
1840	15,908,376	223	71,338	June 25, 1842
1830	11,930,987	240	49,712	May 22, 1832
1820	8,972,396	213	42,124	Mar. 7, 1822
1810	6,584,231	181	36,377	Dec. 21, 1811
1800	4,879,820	141	34,609	Jan. 14, 1802
1790	3,615,823	105	34,436	Apr. 14, 1792
…	…	65	730,000	Constitution, 1780

¹Excludes the population of the District of Columbia, the population of the Territories, the number of Indians not taxed, and (prior to 1870) two-fifths of the slave population,
²This number is the actual number apportioned at the beginning of the decade.
³No apportionment was made after the Census of 1920.
⁴Amended by act of May 30,1872.
⁵Amended by act of Mar, 4,1862.
⁶Amended by act of July 30, 1852.
⁷The minimum ratio of population to Representatives stated in the Constitution (art. 1,sec. 2).

The first attempt to make provision for automatic reapportionment was included in the act for the taking of the Seventh and subsequent censuses (approved May 23, 1850). By specifying the number of Representatives to be assigned and the method to be used, it was hoped to eliminate the need for a new act of Congress every decade and assure an equitable distribution of Representatives. Following the Censuses of 1860 and 1870, however, Congress increased the number of Representatives. When the Census Act of 1850 was superseded in 1879, the automatic feature was discontinued. After each succeeding census up to and including that of 1910, apportionment was by a special act of Congress.

No reapportionment was made after the Census of 1920, the apportionment of 1910 remaining in effect. In 1929, when the act for the taking of the Fifteenth and subsequent censuses was under consideration, it seemed desirable to incorporate some provision which might prevent the repetition of the 1920 experience. A section was, therefore, included in the act which provided, for the 1930 and subsequent censuses, that unless Congress within a specified time enacted legislation providing for apportionment on a different basis, the apportionment should be made automatically by the method last used. In accordance with this act, a report was submitted by the President to Congress on December 4, 1930, showing the apportionment computations both by the method of major fractions (which was the one used in 1910) and by the method of equal proportions. In 1931, in the absence of additional legislation, the automatically effective apportionment followed the method of major fractions.

The Censuses of 1940, 1950, and 1960 were taken under the same law as the Census of 1930, but In 1941 this law was amended to the effect that apportionments based on the 1940 and subsequent censuses should be made by the method of equal proportions. In the application of this method, the Representatives are so assigned that the average population per Representative has the least possible relative variation between one State and any other.

On their admission as States, both Alaska and Hawaii were assigned a single Representative, bringing the total membership in the House of Representatives to 437. This increase was temporary, and the number of Representatives reverted to 435 in the apportionment based on the results of the 1960 Census. Nine States gained Representatives and sixteen lost Representatives in this apportionment. The largest gain was made by California, which gained eight Representatives. Florida gained four; and Arizona, Hawaii, Maryland, Michigan, New Jersey, Ohio, and Texas each gained one. The largest loss, three seats, was incurred by Pennsylvania, Arkansas, Massachusetts, and New York each lost two seats. The twelve States which lost one seat are: Alabama, Illinois, Iowa, Kansas, Kentucky, Maine, Minnesota, Mississippi, Missouri, Nebraska, North Carolina, and West Virginia.

Among the regions, the West contained approximately 49 percent of the total land area of the country and 16 percent of the total population in 1960, whereas the Northeast with about 5 percent of the land area contained approximately 25 percent of the population. The South accounted for about 25 percent of the land area of the country and about 31 percent of the population. The corresponding figures for the North Central States were 21 and 29 percent, respectively. In 1960, there were 273.1 persons per square mile in the Northeast; 68.4 in the North Central States; 02.7 in the South; and 10.0 in the West (table 12).
The Middle Atlantic Division led the divisions with a density of 340.1 persons per square mile of land area, followed by New England with a density of 100.5 and the East North Central Division with a density of 148.0. The density figures for the remaining divisions were all less than 100; and the figure of 8.0 for the Mountain Division was the lowest of all.

The District of Columbia, which is also the city of Washington, had a density of 12,523.9 persons per square mile in 1960. Among the States, there were four-Rhode Island, New Jersey, Massachusetts, and Connecticut-with population densities greater than 500 per square mile. In New York, Maryland, and Pennsylvania, densities ranged from 251.5 to 350.1; densities from 100.4 to 236.9 occurred in the following States: Ohio, Delaware, Illinois, Michigan, Indiana, and California. The population per square mile was less than 10.0 in Alaska, North and South Dakota, and in live of the Mountain States-Montana, Idaho, Wyoming, New Mexico, and Nevada.

Shifts in the ranking of States with respect to density in the period between 1910 and 1900 have not, in general, been very marked. The District of Columbia, Rhode Island, New Jersey, Massachusetts, and Connecticut have occupied one or another of the first five places at each of the six decennial censuses in the 50-year period under consideration, Similarly, during the same period, New Mexico, Montana, Wyoming, Nevada, and Alaska were included among the six least densely settled States at each census, and since 1930 they have occupied the last five places. There were, however, some exceptional shifts. Between 1910 and 1960, California rose from thirty-seventh to fourteenth place, and Florida from thirty-ninth to eighteenth place. On the other hand, Missouri dropped from nineteenth to twenty-eighth place. Since there have been only very minor changes in land area over the 50-year period, these shifts in density rank reflect essentially the corresponding shifts in rank by population size. The largest of the outlying areas of the United States, Puerto Rico, although predominantly rural, was as densely settled as Massachusetts.

The Northeast, with an urban population amounting to about 80 percent of the total population of the region, led all other regions in the percentage of the population classified as urban under the current definition (table 20). A slightly smaller percentage of the total population in the West (77.7 percent) was urban. The percentages of the total population classified as urban in the North Central Region and in the South were 68.7 and 58.5, respectively. In the Middle Atlantic, New England, and Pacific Divisions, the urban population comprised 75 percent or more of the total population, whereas in the East South Central Division slightly less than one-half (48.4 percent) of the population was urban. In the remaining divisions, the percentage urban ranged from 57.2 in the South Atlantic Division to 73.0 in the East North Central Division.

There were four States-New Jersey, Rhode Island, California, and New York-among which the percentage of the population classified as urban was greater than 85 percent. This group of States was followed by five States.-Massachusetts, Illinois, Connecticut, Hawaii, and Texas-in which the percentage varied from 75.0 to 83.6. At the lower end of the distribution, the percentage urban for North Dakota was 35.2 and for Mississippi, 37.4. For an additional five States-Alaska, West Virginia, Vermont, South Dakota, and North Carolina-this percentage varied from 37.9 to 39.5. The range in the remaining 34 States was from 41.2 percent for South Carolina to 74.9 percent in Utah. The District of Columbia is completely urban.

Changes in the urban and rural population under the current definition differed considerably in the various regions, except in the Northeast. In the West, the urban and rural percentages of increase were 55.3 and 1.7, respectively, and in the North Central Region the corresponding percentages were 24.5 and 1.1. In the South, the urban rate of increase was 40.1 percent, whereas the rural population declined by 5.9 percent. In the Northeast, however, the urban rate of increase of 14.2 percent was only about one and one-half times as large as the corresponding rural rate of increase, 9.0 percent.

The patterns of change in the urban and rural population among the geographic divisions fall into several distinct types. However, in all of the divisions, the rate of growth of the urban population during the decade exceeded' the rate of growth of the rural population. The West North Central, East South Central, West South Central, and Mountain Divisions were characterized by substantial rates of growth in urban areas and by actual losses in rural areas. In the East North Central, South Atlantic, and Pacific Divisions, both the urban and rural populations increased; but the urban rates of increase were several times as great as the rural rates. In both component divisions of the Northeast, the New England and Middle Atlantic Divisions, the urban rates of increase were below the rate of growth of the total population of the country as a whole, and in comparison with other divisions only moderately in excess of the rural rates of increase.
The rates of urban and rural increase among the States (exclusive of the District of Columbia) show a similar type of variability. There were 28 States (including all of the States of the West North Central, East South Central, and West South Central Divisions) in which the urban population Increased but decreases occurred in the rural population. Among this group of States were Arkansas, Mississippi, and West Virginia, the three States in which the total population decreased during the decade; In these States the rates of urban increase were, nonetheless, 21.4, 35.2, and 2,4 percent, respectively. There were 19 States in which both the urban and the rural population increased and in which the urban rate of growth exceeded the rural rate of growth. In the remaining 3 States-Maine, Massachusetts, and New York-the rural rate of increase exceeded the urban rate. In summary, the urban population Increased in every State during the decade ending in 1900, whereas the rural population declined in a majority of the States.

The net shift of persons from the rural to the urban population as the result of the change in definition amounted to 0.8 percent of the total population of the United States (table 19). The corresponding percentages for the regions were as follows: the Northeast, 7.4; the North Central Region, 4.8; the South, 5.8; and the West, 11.5.

Generally, the net effect of the change in definition was to increase the percent urban among the States, in three New England States-Massachusetts, New Hampshire, and Rhode Island-however, the net effect of the change was to decrease the percentage of the population classified as urban. In Wyoming, the change had no effect on the distribution of the population by urban and rural residence. Among all the remaining States, however, the change in definition resulted in net shifts from the rural to the urban category. These shifts ranged from 0,2 percent of the total population of North Dakota to 33.0 percent of that of Delaware.

The net shift affected by the change in definition is, of course, an index of the degree to which new areas of population concentration are legally recognized by annexation or incorporation. In States where such recognition is widespread, the net addition to the percent urban is relatively small, whereas in States where such recognition was at a minimum, the net addition to the percent urban was large. In the New England States, the situation is complicated by the application of the special rules of the previous definition, Here, apparently, in the three States in which there was a net loss in urban population as the result of the change in definition, the gain attributable to the special rules of the previous definition was greater than the gain from the urban-fringe areas, unincorporated places, and urban towns of the current definition.

Although the change in the definition of urban-rural residence has produced some change in rank according to percent urban, there are certain Slates which have ranked consistently high, and other States consistently low, under both definitions in 19G0 and under the previous definition in 1900 and 1910 (table G). The District of Columbia, viewed for this purpose as a State with its entire population urban, ranked first in each instance. Likewise, New Jersey, Rhode Island, California, New York, Massachusetts, and Illinois were among the first 10 places, and North Dakota, Mississippi, Alaska, South Dakota, and North and South Carolina fell among the last 10 places, in each of the three distributions.

The change in definition did, however, in a number of instances make substantial changes in rank in 1960. Delaware, for example, ranked twenty-third under the current definition, but fifty-first under the previous definition, and for Maryland the corresponding ranks were seventeenth and thirtieth. In both of these States there had been a decline in the population of the principal city which constituted a large part of the urban population of the State, but a large growth of suburban population outside incorporated places. The current definition recognized this latter growth, but the previous definition did not. Both of the States showed appreciable losses between 1010 and 1960 in rank under the previous definition. The current definition, therefore, serves to correct the impression that urban population is decreasing in these States. Although the changes in rank are not large, the same pattern occurs in States such as New York, California, and Connecticut, for which there was a decrease in rank under the previous definition between 1910 and 1960 but a higher rank in the latter year under the current definition.

Since 1790, not only have there been changes in. the boundaries of the Thirteen Original States, but the whole process of converting newly acquired areas, first into Territories and then into States, involved a considerable number of boundary" changes before the State boundaries, as they now exist, were established. The history of major changes as they relate to the 50 States and the District of Columbia as now constituted is outlined below:

Alabama.-Alabama was organized as a Territory in 1817 from the eastern part of Mississippi Territory and was admitted to the Union in 1819 as the twenty-second State with boundaries as at present.

Alaska.-Alaska was acquired by purchase from Russia in 1867 and was organized as a Territory in 1912. In 1959, Alaska was admitted to the Union as the forty-ninth State.

Arizona.-Arizona was organized as a Territory in 1863 from the western part of the Territory of New Mexico. Part of the Territory was annexed in 1867 by
Nevada, leaving the Territory with boundaries the same as those of the present State. Arizona was admitted to the Union in 1912 as the forty-eighth State.

Arkansas.-Arkansas was organized as a Territory in 1819 with boundaries which also included most of the present area of Oklahoma. The area of the Territory was reduced in 1824 and 1828 to substantially the present boundaries of the State. It was admitted to the Union as the twenty-fifth State in 1836 with boundaries substantially as at present.
California.-California was organized) as a State from a part of the area acquired from Mexico in 1848 and was admitted to the Union in 1850 as the thirty-first State with boundaries as at present.

Colorado.-Colorado was organized as a Territory in 1861 from parts of Kansas, Nebraska, New Mexico, and Utah Territories. In 1876, without change in boundaries and with boundaries as at present, it was admitted to tie Union as the thirty- eighth State.

Connecticut.-Connecticut was one of the Thirteen Original States.

Delaware.-Delaware was one of the Thirteen Original States.

District of Columbia.-The District of Columbia, formed from territory ceded by Maryland and Virginia, was established as the seat of the Federal Government in accordance with acts of Congress passed in 1790 and 1791. Its boundaries, as defined in 1791, included the present area, together with about 30 square miles in Virginia. In 1846 the area south of the Potomac River was retroceded to Virginia, leaving the District of Columbia with its present limits.

Florida.-Florida was organized as a Territory in 1822, with boundaries as at present, from the area purchased from Spain in 1819 and transferred to the United States in 1821. It was admitted to the Union in 1845 as the twenty-seventh State.

Georgia.-Georgia was one of the Thirteen Original States. At the close of the Revolution, it included territory extending westward to the Mississippi River, constituting most of the area now in Alabama and Mississippi. In 1798 part of this area was organized as the Territory of Mississippi. In 1802 Georgia ceded to the United States all its claims to the region west of its present western boundary and acquired a small strip of land along its northern boundary. These changes left the State with its present boundaries.

Hawaii.-Hawaii, by voluntary action, ceded its sovereignty to the United States in 1898 and was organized as a Territory in 1900. In August 1959, Hawaii was admitted to the Union as the fiftieth State.

Idaho.-Idaho was organized as a Territory in 1863. Its area was reduced in 1804 by the organization of Montana Territory and in 1868 by the organization of Wyoming Territory. Idaho attained its present boundaries in 1873 with the transfer of six square miles to Montana following a resurvey of the Continental Divide. Idaho was admitted to the Union in 1890 as the forty-third State.

Illinois.-Illinois, organized as a Territory in 1809 from the western part of Indiana Territory, comprised at that time all of the present State of Illinois, almost all of Wisconsin, and parts of Michigan and Minnesota. In 1818 that portion of the Territory lying within the present boundaries of Illinois was admitted to the Union as the twenty-first State.

Indiana.-The Territory of Indiana was organized from the western part of the Territory Northwest of the River Ohio in 1800, at which time it comprised nearly all of the present State of Indiana, together with an area now constituting Illinois, Wisconsin, northeastern Minnesota, and western Michigan. In 1802 an area now constituting the remainder of Michigan was added, and in 1802 and 1803 minor revisions of the eastern boundary took place. The area of the Territory was greatly reduced by the organization of Michigan Territory in 1805 and of Illinois Territory in 1809. In 1816, with the addition of a small strip of land along the northern boundary and the separation of an area in the Upper Peninsula, Indiana was admitted to the Union as the nineteenth State with boundaries as at present.

Iowa.-Iowa was organized as a Territory in 1838 with boundaries that included, in addition to the present area of the State, the eastern parts of the present States of North Dakota and South Dakota and the western part of the present State of Minnesota. Iowa was admitted to the Union In 1846 as the twenty-ninth State with boundaries substantially as at present.

Kansas.-The area now comprising Kansas and part of Colorado was organized as the Territory of Kansas in 1854, and in 1861 that portion of the Territory lying within the present boundaries of Kansas was admitted to the Union as the thirty-fourth State.

Kentucky.-Kentucky, originally a part of Virginia, was admitted to the Union in 1792 as the fifteenth State with boundaries substantially as at present.

Louisiana.-The greater part of the area now constituting Louisiana was organized in 1804 as the Territory of Orleans. It included at that time the Baton Rouge
District-that part of the present State lying east of the Mississippi River-but excluded the southwestern part of the present State-that part lying west of the Louisiana Purchase boundary. In 1812 all the present area of Louisiana except the Baton Rouge District was admitted to the Union as the eighteenth State, and upon the addition of the district a few days later Louisiana assumed its present boundaries.

Maine.-Maine, originally a part of Massachusetts, was admitted to the Union in 1820 as the twenty-third State.

Maryland.-Maryland was one of the Thirteen Original States. In 1791 its area was reduced by the formation of the District of Columbia.

Massachusetts.-Massachusetts was one of the Thirteen Original States. In 1820 Maine, previously a part of Massachusetts was admitted to the Union as a separate State, leaving Massachusetts with boundaries substantially as at present.

Michigan.-Michigan was organized as a Territory in 1805 from the northeastern part of Indiana Territory and comprised the greater part of the area of the present State, including the Lower Peninsula and the eastern end of the Upper Peninsula, and a small part of the present State of Indiana. In 1816 a narrow strip at the southern limit of Michigan Territory was annexed to Indiana Territory. In 1818, when Illinois was admitted as a State, all of Illinois Territory north of the State of Illinois was transferred to Michigan Territory. This transferred area comprised almost all of the present State of Wisconsin, part of Minnesota, and the western part of the Upper Peninsula of Michigan. At the same time a section of unorganized territory, formerly part of Indiana Territory, was annexed by the Territory of Michigan. This annexation comprised the middle portion of the Upper Peninsula and a very small part of Wisconsin not formerly included. In 1834 Michigan Territory was further enlarged by the annexation of that part of Missouri Territory now comprising all of Iowa, the remainder of Minnesota not previously included, and parts of North and South Dakota. With the organization of Wisconsin Territory and the legal cession of a small area to Ohio in 1836, Michigan Territory assumed the limits of the present State. Michigan was admitted to the Union as the twenty-sixth State in 1837.

Minnesota.-Minnesota was organized as a Territory in 1849 from unorganized area formerly within the Territories of Iowa and Wisconsin. It included an area now comprising the State of Minnesota, the eastern parts of the States of North and South Dakota, and a small part of Nebraska. In 1858 that part of the Territory lying within the present boundaries of Minnesota was admitted to the Union as the thirty-second State.

Mississippi.-Mississippi was organized as a Territory in 1798, at which time it included territory now comprising the south central parts of Mississippi and Alabama. The area of the Territory was enlarged in 1804 by the addition of land now comprising the northern parts of Mississippi and Alabama. Its area was further enlarged in 1812 by the addition of the extreme southern portions of the present States of Mississippi and Alabama. In 1817 the eastern part of the Territory was taken to form the Territory of Alabama, and Mississippi was admitted to the Union as the twentieth State with boundaries substantially as at present.

Missouri.-The Territory of Missouri, the name given in 1812 to the former Territory of Louisiana, comprised at that time all of the Louisiana Purchase except the part included in the State of Louisiana. The State of Missouri, formed from a small part of the Territory, was admitted to the Union in 1821. In 1836, when the present northwest corner of the State was added, Missouri assumed its present limits.

Montana.-Montana was organized as a Territory in 1864 from the northeastern part of Idaho Territory with boundaries substantially the same as those of the present State. It was admitted to the Union in 1889 as the forty-first State.

Nebraska.-Nebraska was organized as a Territory in 1854 from unorganized territory originally part of the Louisiana Purchase. Its boundaries included, in addition to the present area of the State, parts of the present States of North and South Dakota, Montana, Wyoming, and Colorado. The area of the Territory was greatly reduced in 1861 by the organization of Dakota and Colorado Territories. At the same time a small area was added to the western part of the Territory. The area was again reduced in 1863 by the organization of Idaho Territory. Nebraska was admitted to the Union in 1867 as the thirty-seventh State with boundaries substantially as at present. In 1870 and 1882 small tracts of land were transferred from the Dakota Territory to Nebraska, and in 1943 small tracts of land were transferred between Iowa and Nebraska.

Nevada.-Nevada, when organized as a Territory in 1861 from part of Utah Territory, comprised only the western part of the present State. In 1864 Nevada was admitted to the Union as the thirty-sixth State, its area having been enlarged in 1862 by the annexation from Utah Territory of a strip of land more than 50 miles wide. The State was enlarged in 1866 by annexation from Utah and in 1867, with an annexation from Arizona; Nevada assumed its present limits.

New Hampshire.-New Hampshire was one of the Thirteen Original States.

New Jersey.-New Jersey was one of the Thirteen Original States.

New Mexico.-The Territory of New Mexico was organized in 1850 from the area now comprising the greater parts of the States of New Mexico and Arizona, together with small portions of Colorado and Nevada. The Territory was enlarged by the addition of the Gadsden Purchase in 1854 and reduced by the organization of Colorado Territory in 1861, with the organization of Arizona Territory in 1863; the area of New Mexico was reduced to substantially the present area of the State. New Mexico was admitted to the Union in 1912 as the forty-seventh State.

New York.-New York was one of the Thirteen Original States. New York dropped its claim to Vermont after the latter was admitted to the Union as a separate State in 1791. With the annexation of a small area from Massachusetts in 1853, New York assumed its present boundaries.

North Carolina.-North Carolina was one of the Thirteen Original States,

North Dakota.-North Dakota was organized as a State from part of Dakota Territory with boundaries as at present and was admitted to the Union in 1889.

Ohio.-Ohio was organized from part of the Territory Northwest of the River Ohio in 1802 and with minor revisions of the western boundary was admitted to the Union as the seventeenth State in 1803. With the settlement of a boundary dispute with Michigan Territory in 1836, Ohio assumed its present boundaries.

Oklahoma.-The Territory of Oklahoma was organized, in 1890 from the western part of Indian Territory and the Public Land Strip, originally a part of Texas. In 1893 the Territory was enlarged by the addition of the Cherokee Outlet, which fixed part of the present northern boundary. In 1907 the Territory and the remaining part of the Indian Territory were combined and admitted to the Union as the forty-sixth State with boundaries substantially as at present. Upon the settlement in 1930 of a boundary dispute with Texas, Oklahoma assumed its present: limits.

Oregon.-Oregon was organized as a Territory in 1848, at which time it included the area now constituting the States of Oregon, Washington, Idaho, and parts of western Montana and Wyoming. The area of the Territory was greatly reduced in 1853 by the organization of the Territory of Washington. In 1859, with the transfer to Washington Territory of the area now comprising southern Idaho, western Wyoming, and a small tract in western Montana, Oregon assumed its present boundaries and was admitted to the Union as the thirty-third State,

Pennsylvania.-Pennsylvania was one of the Thirteen Original States. With the purchase of a small tract of land in its northwestern corner from the Federal Government in 1792, Pennsylvania assumed its present boundaries.

Rhode Island.-Rhode Island was one of the Thirteen Original States.

South Carolina-South Carolina was one of the Thirteen Original States.

South Dakota.-South Dakota was organized as a State from part of Dakota Territory and was admitted to the Union in 1889.

Tennessee.-The Territory South of the River Ohio was organized in 1790, at which time it included the present State of Tennessee and parts of Mississippi, Alabama, and Georgia. In 1796 Tennessee was admitted to the Union as the sixteenth State with boundaries substantially as at present.

Texas.-Texas, originally a part of Mexico, won its independence by revolution in 1835 and 1836 and continued as an independent republic until 1845, when it was annexed to the United States and admitted to the Union as the twenty-eighth State. At this time it included area now comprising parts of Colorado, Kansas, New Mexico, Oklahoma, and Wyoming, in 1850, with the transfer to the United States of the territory now in these other States; Texas assumed practically its present boundaries. Upon settlement of a boundary dispute with Oklahoma in 1980, Texas assumed its present boundaries.

Utah.-The Territory of Utah was organized in 1850, at which time it comprised, in addition to the area of the present State, areas now constituting western Colorado, southwestern Wyoming, and the greater part of Nevada. The area of the Territory was reduced in 1861 by the organization of Nevada and Colorado Territories and by a transfer to Nebraska Territory. It was reduced again in 1862 by the eastward extension of the Territory of Nevada and in 1866 by a similar extension of the State of Nevada and In 1868 by the organization of Wyoming Territory- Utah was admitted to the Union in 1896 as the forty-fifth State with boundaries as at present.

Vermont.-Vermont was admitted to the Union in 1791 as the fourteenth State and was the first to be admitted after the adoption of the Constitution by the Thirteen Original States.

Virginia.-Virginia, one of the Thirteen Original States, included in 1790 the areas now constituting the States of Kentucky and West Virginia. The area of the State was reduced in 1791 by the formation of the District of Columbia and in 1792 by the admission of Kentucky into the Union as a separate State; the area was enlarged in X846 by the retrocession of the part of the District of Columbia south of the Potomac but was further reduced in 1863 by the admission of West Virginia into the Union as a separate State. In 1866 two additional counties (Berkeley and Jefferson) were annexed to West Virginia, leaving the boundaries of Virginia as at present.

Washington.-Washington was organized as a Territory in 1853 from part of Oregon Territory, and included an area now comprising the State of Washington, northern Idaho, and part of Montana. In 1859 upon the admission of Oregon as a State, the remaining portion of Oregon Territory, comprising the rest of Idaho and parts of Montana and Wyoming, was added to the Territory of Washington. The area of the Territory was reduced to the present limits of the State in 1863, upon the organization of Idaho Territory. Washington was admitted to the Union in 1889 as the forty-second State.

West Virginia.-West Virginia, formed from 48 counties of Virginia, was admitted to the Union in 1863 as the thirty-fifth State. In 1866, with the annexation of two additional counties (Berkeley and Jefferson) from Virginia, the boundaries were established as at present.

Wisconsin.-Wisconsin was organized as a Territory in 1836 from that part of Michigan Territory which lay west of the present limits of the State of Michigan. As originally constituted, the Territory included the present States of Wisconsin, Iowa, Minnesota, the eastern parts of North and South Dakota, and a small part of Nebraska. In 1838, that part of the Territory lying west of the Mississippi River and a line drawn due north from its source to the Canadian boundary was organized as the Territory of Iowa. In 1848, that part of the Territory lying within the present boundaries of the State was admitted to the Union as the thirtieth State.

Wyoming.-Wyoming was organized as a Territory in 1868 with boundaries as at present from parts of Dakota, Idaho, and Utah Territories, It was admitted to the Union in I860 as the forty-fourth State.

Table G. Rank of States According to Percent of Population Classified as Urban: 1960 and 1910

Rank	1960				1910
	Current urban definition		Previous urban definition
	State	Percent urban	State	Percent urban	State	Percent urban
1	Dist. of Col	100.0	Dist. of Col	100.0	Dist. of Col	100.0
2	New Jersey	88.6	Rhode Island	89.9	Rhode Island	91.0
3	Rhode Island	86.4	Massachusetts	86.8	Massachusetts	89.0
4	California	86.4	New Jersey	82.6	New York	78.9
5	New York	85.4	Illinois	75.9	New Jersey	76.4
6	Massachusetts	83.6	New York	72.8	Connecticut	65.6
7	Illinois	80.7	Texas	72.7	California	61.8
8	Connecticut	78.3	California	71.7	Illinois	61.7
9	Hawaii	76.5	Arizona	69.9	Pennsylvania	60.4
10	Texas	76.0	Hawaii	69.3	Ohio	55.9
11	Utah	74.9	Connecticut	69.0	Washington	53.0
12	Arizona	74.5	Ohio	67.4	New Hampshire	51.8
13	Florida	73.9	Utah	66.5	Maryland	50.8
14	Colorado	73.7	Nevada	66.3	Colorado	50.3
15	Ohio	73.4	Pennsylvania	65.6	Delaware	48.0
16	Michigan	73.4	Michigan	65.0	Michigan	47.2
17	Maryland	72.7	Florida	62.2	Utah	46.3
18	Pennsylvania	71.6	Colorado	62.1	Oregon	45.6
19	Nevada	70.4	Wisconsin	62.1	Wisconsin	43.0
20	Washington	68.1	New Mexico	61.8	Indiana	42.4
21	Missouri	66.6	Missouri	61.3	Missouri	42.3
22	New Mexico	65.9	Oklahoma	61.0	Minnesota	41.0
23	Delaware	65.6	Minnesota	61.0	Montana	35.5
24	Wisconsin	63.8	New Hampshire	59.8	Maine	35.3
25	Louisiana	63.3	Washington	58.4	Arizona	31.0
26	Oklahoma	62.9	Indiana	56.8	Hawaii	30.7
27	Indiana	62.4	Wyoming	56.8	Iowa	30.6
28	Oregon	62.2	Kansas	56.4	Louisiana	30.0
29	Minnesota	62.2	Louisiana	56.2	Wyoming	29.0
30	Kansas	61.0	Maryland	56.2	Kansas	29.1
31	New Hampshire	58.3	Oregon	53.4	Florida	29.1
32	Wyoming	56.8	Iowa	52.2	Vermont	27.8
33	Virginia	55.6	Nebraska	52.0	Nebraska	26.1
34	Georgia	55.3	Alabama	51.7	Kentucky	24.3
35	Alabama	54.8	Georgia	49.8	Texas	24.1
36	Nebraska	54.3	Virginia	48.7	Virginia	23.1
37	Iowa	53.0	Montana	46.3	Idaho	21.5
38	Tennessee	52.3	Tennessee	45.7	Georgia	20.6
39	Maine	51.3	Arkansas	41.6	Tennessee	20.2
40	Montana	50.2	Idaho	41.4	Oklahoma	19.2
41	Idaho	47.5	Maine	39.9	West Virginia	18.7
42	Kentucky	44.5	South Dakota	39.0	Alabama	17.3
43	Arkansas	42.8	Alaska	37.9	Nevada	16.3
44	South Carolina	41.2	Kentucky	37.7	South Carolina	14.8
45	North Carolina	39.5	Vermont	37.0	North Carolina	14.4
46	South Dakota	39.3	Mississippi	36.2	New Mexico	14.2
47	Vermont	38.5	North Carolina	36.2	South Dakota	13.1
48	West Virginia	38.2	West Virginia	35.8	Arkansas	12.9
49	Alaska	37.9	North Dakota	35.1	Mississippi	11.5
50	Mississippi	37.7	South Carolina	34.3	North Dakota	11.0
51	North Dakota	35.2	Delaware	32.6	Alaska	9.5

The major objective of the Bureau of the Census in delineating urbanized areas was to provide a better separation of urban and rural population in the vicinity of the larger cities, but individual urbanized areas have proved to be useful statistical areas. They correspond to what are called "conurbations" in some other countries. An urbanized area contains at least' one city of 50,000 inhabitants or more in 1960,⁵ as well as the surrounding closely settled incorporated places and unincorporated areas that meet the criteria listed below. An urbanized area may be thought of as divided into the central city, or cities, and the remainder of the area, or the urban fringe. All persons residing in an urbanized area are included in the urban population.

It appeared desirable to delineate the urbanized areas in terms of the 1960 Census results rather than on the basis of information available prior to the census as was done in 1950. For this purpose, a peripheral zone around each 1950 urbanized area and around cities that were presumably approaching a population of 50,000 was recognized. Within the unincorporated parts of this zone small enumeration districts were established, usually including no more than one square mile of land area and no more than 75 housing units. ⁶
Arrangements were made to include within the urbanized area those enumeration districts meeting specified criteria of population density as well as adjacent incorporated places. Since the urbanized area outside incorporated places was defined in terms of enumeration districts, the boundaries of the urbanized area for the most part follow such features as roads, streets, railroads, streams, and other clearly defined lines which may be easily identified by census enumerators in the field and often do not conform to the boundaries of political units.

In addition to its central city or cities, an urbanized area contains the following types of contiguous areas, which together constitute its urban fringe:

1. Incorporated places with 2,500 inhabitants or more.
2. Incorporated places with less than 2,900 inhabitants, provided each has a closely settled area of 100 housing units or more.
3. Towns in the New England States, townships in New Jersey and Pennsylvania, and counties elsewhere which are classified as urban.
4. Enumeration districts in unincorporated territory with a population density of 1,000 Inhabitants or more per square mile. (The areas of large nonresidential tracts devoted to such urban land uses as railroad yards, factories, and cemeteries were excluded in computing the population density of an enumeration district.)
5. Other enumeration districts in unincorporated territory with lower population density provided that they served one of the following purposes:
a. To eliminate enclaves.
b. To close indentations in the urbanized areas of one mile or less across the open end.
c. To link outlying enumeration districts of qualifying density that were no more than 1 ½ miles from the main body of the urbanized area.
A single urbanized area was established for cities in the same standard metropolitan statistical area if their fringes adjoin. Urbanized areas with central cities in different standard metropolitan statistical areas are not combined, except that a single urbanized area was established in the New York-Northeastern New Jersey Standard Consolidated Area, and in the Chicago- Northwestern Indiana Standard Consolidated Area.
Urbanized areas were first delineated for the 1950 Census, in 1950, urbanized areas were established in connection with cities having 50,000 inhabitants or more according to the 1940 Census of Population or a later census prior to 1950; in 1960, urbanized areas were established in connection with cities having 50,000 inhabitants or more according to the 1960 Census of Population.
The boundaries of the urbanized areas for 1960 will not conform to those for 1950, partly because of actual changes in land use and density of settlement, and partly because of relatively minor changes in the rules used to define the boundaries. The changes in the rules include the following:
1. The use of enumeration districts to construct the urbanized areas in 1960 resulted in a less precise definition than in 1950 when the limits were selected in the field using an individual city-type block as the unit of area added. On the other hand, the 1900 procedures produced an urbanized area based on the census results rather than an area defined at least a year before the census, as in 1950.
2. Unincorporated territory was included in the 1960 urbanized area if it contained at least 1,000 persons per square mile, which is a somewhat different criterion from the 500 dwelling units or more per square mile of the included 1950 unincorporated areas.
3. The 1960 areas include those entire towns in New England, townships in New Jersey and Pennsylvania, and counties that are classified as urban in accordance with the criteria listed in the section on urban-rural residence. The 1950 criteria permitted the exclusion of portions of those particular minor civil divisions.
4. In general, however, the urbanized areas of 1950 and 1960 are based on essentially the same concept, and the figures for a given urbanized area may be used to measure the population growth of that area.

Any city in an urbanized area which is a central city of a standard metropolitan statistical area (see the following section) is also a central city of the urbanized area, with but two exceptions, the names of the central cities appear in the titles of the areas. The central cities of the New York-Northeastern New Jersey Area are the central cities of the New York, Newark, Jersey City, and Paterson-Clifton-Passaic Standard Metropolitan Statistical Areas. Likewise, the central cities of the Chicago-Northwestern Indiana Area are the central cities of the Chicago and Gary-Hammond-East Chicago Standard Metropolitan Statistical Areas.

Slightly more than one-half of the total, and more than three-fourths of the urban, population of the United States was living in the 213 urbanized areas in 1960 (table 5). Of the 95.8 million persons living in urbanized areas, 58.0 million were in the 254 central cities and about 37.9 million were living in the urban-fringe areas. In these fringe areas there were 27.3 million persons living in the 1,580 urban places; about 700,000 living in the 596 incorporated places under 2,500 inhabitants; and 9.9 million living in other urban territory. The sum of these last two numbers-10.5 million-represents the persons in urban territory living outside urban places, and, consequently, the net addition to the urban population attributable to the urbanized area delineations.

In population, the urbanized areas ranged in size from the Tyler (Texas) Urbanized Area, which had a population of 51,739, to the New York-Northeastern New Jersey Urbanized Area, which had a population of 14,114,927 (table 23). The 16 urbanized areas with more than 1,000,000 inhabitants had a combined population of 51,785,410, or more than one-half of the population of the 213 areas. At the other extreme, the 4,592,899 persons living in the 60 urbanized areas of under 100,000 inhabitants represented less than one-twentieth of the total population in urbanized areas.

Six out of ten persons living in urbanized areas were residents of central cities. The proportion of the population of urbanized areas living in the central city or cities, however, varied greatly among the areas, ranging from a low of 27.2 for the Wilkes-Barre (Pa.) Urbanized Area to a high of 100 percent for the Meriden, Conn.; Lewiston-Auburn, Maine; Raleigh, N.C., areas; and three urbanized areas in Texas-Amarillo, Laredo, and San Angelo. There were 87 urbanized areas with 80 percent or more of their population in the central city or cities. On the other hand, 3 areas-West Palm Beach, Fla.; Boston, Mass.; and Wilkes-Barre, Pa.-had fewer than one-third of their inhabitants living in central cities (table 22).

The population per square mile of land area for all 213 urbanized areas was 3,752 (table 22). Two areas-York, Pa., and New York-Northeastern New Jersey- had densities in excess of 7,000, and 29 areas had densities of less than 2,000. In all areas combined, the density of the central cities was more than double that of the urban fringe areas. In 13 areas, however, the density of the urban fringe exceeded that of the central city. Population densities for both central city and urban fringe were highly variable from area to area. The extremely low densities in the urban fringe areas of some cities are in large part attributable to the Inclusion in the urbanized areas of land devoted to urban uses other than residential use, such as industrial areas, railroad yards, and airports.

The primary divisions of the States are, in general, termed counties; but in Louisiana these divisions are known as parishes. Alaska Is divided into 24 election districts, Included here as the equivalents of counties. There are also a number of cities which are Independent of any county organization and thus constitute primary divisions of their States, namely, Baltimore in Maryland, St. Louis in Missouri, and 82 cities in Virginia. The District of Columbia, which is not divided into counties, also is included here as the equivalent of a county, as are the three parts of Yellowstone National Park in Idaho, Montana, and Wyoming. There were 3,072 counties and parishes in the United States in 1960 and 62 county equivalents, making a total of 3,134.

The number of counties declined by three between 1950 and 1960. Armstrong County, S. Dak., was annexed by Dewey County; Elizabeth City County, Va., was consolidated with Hampton city; and Warwick County, Va., was consolidated with Newport News city. The number of county equivalents in conterminous United States increased by five. Five cities in Virginia-Covington, Galax, Norton, South Boston, and Virginia Beach-became independent of county organization during the decade. Alaska was redistricted after 1950, and its judicial divisions were replaced by 24 election districts. Changes in the number of counties were fairly frequent some decades ago but have become progressively rarer. These changes, as well as changes of county boundaries, are listed in the notes to tables 6 and 7 of the PC(1)-A State chapters and in the reports of other censuses.

The counties ranged in population from Hinsdale County, Colo., which had 208 inhabitants, to Los Angeles County, Calif., which had 6,038,771 inhabitants (table 24). Fifteen additional counties-San Diego, Calif.; Cook, III.; Middlesex, Mass.; Wayne, Mich.; Bronx, Erie, Kings, Nassau, New York, and Queens, N.Y.; Cuyahoga, Ohio; Allegheny and Philadelphia, Pa.; Harris, Texas; and Milwaukee, Wis.-had 1,000,000 inhabitants or more. These 16 counties had a combined population of 33,589,591, or nearly one-fifth of the population of the United States (table H). On the other hand, the 855 counties and county equivalents having fewer than 10,000 inhabitants had a combined population of 5,082,674, or not quite 3 percent of the population. Despite the increase of almost one- fifth in the population of the United States as a whole, the median county population was 19,762 in 1960 as against 19,873 in 1950.

Table H.-Population in Groups of Counties Classified According to Size: 1960 and 1950

Size of county	1960			1950
	Number	Percent	Population	Number	Percent	Population
Total	13,134	100.0	179,323,175	3,1122	100.0	151,325,798
1,000,000 or more	16	0.5	33,589,591	11	0.4	24,837,059
500,000 to 1,000,000	49	1.6	32,879,300	31	1.0	20,753,791
250,000 to 500,000	61	1.9	20,764,647	49	1.6	16,982,715
100,000 to 250,000	177	5.6	27,787,023	151	4.9	23,478,633
50,000 to 100,000	293	9.3	20,819,160	259	8.8	18,182,986
25,000 to 50,000	589	18.8	20,921,794	651	20.9	22,830,614
10,000 to 25,000	1,094	34.9	17,988,386	1,182	38.0	19,550,358
5,000 to 10,000	561	17.9	4,183,933	516	16.6	3,921,320
2,500 to 5,000	202	6.4	757,593	177	5.7	678,910
1,000 to 2,500	72	2.3	129,994	66	2.1	119,738
Under 1,000	20	0.6	11,154	19	0.6	9,675
Cumulative Summary
100,000 or more	303	9.7	115,011,161	242	7.8	86,032,198
25,000 or more	1,185	37.8	158,252,115	1,152	37.0	127,045,797
10,000 or more	2,279	72.7	174,240,501	2,334	75.0	146,596,155
Median population	…	…	19,762	…	…	19,873

¹ Includes 3,008 counties; 64 parishes in Louisiana; 24 election divisions in Alaska; 32 independent cities in Virginia; Baltimore city, Md.; St. Louis city, Mo.; the Districts of Columbia; and the parts of Yellowstone National Park in Idaho, Montana, and Wyoming.
²Includes 3,011 counties; 64 parishes in Louisiana; 4 judicial districts in Alaska; 32 independent cities in Virginia; Baltimore city, Md.; St. Louis city, Mo.; the Districts of Columbia; and the parts of Yellowstone National Park in Idaho, Montana, and Wyoming.

Despite the record gain of 28 million in the population of the United States as a whole, nearly one-half of the counties lost population and about one- fourth lost 10 percent or more (table 25). Of the 3,110 counties and county equivalents (excluding Alaska for which comparable figures for 1950 are not available), 1,537, or 49.4 percent, lost population, and 782, or 25.1 percent, lost 10 percent or more. Of the 1,573 counties which gained population, 953, or 60.6 percent, increased by 10 percent or more and 570, or 36.2 percent, increased by 20 percent or more.

More than three out of every four counties in the Northeast, and three out of every five counties in the West, increased in population. In both the North Central States and the South, however, more than half the counties lost population. Connecticut and Delaware, which have very few counties, were the only States in which all counties increased in population. Forty- six counties, as well as three independent cities in Virginia, doubled in population between 1950 and 1960 (table J). Only seven of these counties were located outside the South or the West. Seventeen of these counties and the three independent cities were in the South Atlantic States and eleven were in the Mountain States. Twenty-six of the fastest growing counties and the three independent cities were metropolitan counties; twenty counties were in nonmetropolitan areas. Six of the seven counties in the Northeast and the North Central States that doubled in population were in metropolitan areas. The standard metropolitan statistical areas in the South Atlantic States included eight counties and three independent cities that doubled in population; in the Mountain States, five counties in metropolitan areas doubled in population.

Some of the greatest rates of increase or decrease in the population of counties or county equivalents were attributable to boundary changes. The fastest growing county or county equivalent In the United States between 1950 and 1960 was the independent city of Hampton, Va., which had a population increase of 1,396.1 percent. This spectacular gain was due in large part to consolidation with Elizabeth City County. The next largest increase was 3T1.1 percent, In Brevard County, Fla. At the other extreme, the largest percentage decline was experienced in Norfolk County, Va., which had a decline of 48.4 percent. This loss, however, resulted from the annexation of a considerable part of the county by the neighboring independent city of Norfolk. The next largest percentage decline-47.6 percent-was in Allegheny County, Va. This loss resulted from the detachment of Covington town, which became an independent city.

Puerto Rico Is divided, for purposes of local government, into 76 areas called municipios. The number of municipios in 1960 was one less than in 1950 due to the annexation of Rio Pledras to San Juan municipio during the decade.

Table J.-Counties with Population Increase of 100 Percent or More between 1950 and 1960

Rank	County	1960	1950	Increase, 1950 to 1960
				Number	Percent
1	Hampton, Va1	89,258	25,966	83,292	1,396.1
2	Brevard, Fla.	111,435	23,653	87,782	371.1
3	Pulaski, Mo.	46,567	10,392	36,175	348.1
4	Broward, Fla.	333,946	83,933	250,018	297.9
5	Grand, Utah	6,345	1,903	4,442	233.4
6	Orange, Calif.	703,925	216,224	487,701	225.6
7	Daggett, Utah	1,164	364	800	219.8
8	Adams, Colo.	120,296	40,234	80,062	199.0
9	Charlotte, Fla.	12,594	4,286	8,308	193.8
10	San Juan, N. Mex.	53,306	18,292	35,014	191.4
11	St. Bernard, La.	32,186	11,087	21,099	190.3
12	Fairfax, Va.	275,002	98,557	176,445	179.0
13	Andrews, Texas	13,450	5,002	8,448	168.9
14	Newport News, Va.1	113,662	342,358	71,304	168.3
15	Sarasota, Fla.	76,895	28,827	48,068	166.7
16	Clark, Nev.	127,016	48,289	78,727	163.0
17	Midland, Texas	67,717	25,785	41,932	162.6
18	Elmore, Idaho	16,719	6,687	10,032	150.0
19	Otero, N. Mex.	36,976	14,909	22,067	148.0
20	Randall, Texas	33,913	13,774	20,139	146.2
21	Collier, Fla.	15,753	6,488	9,265	142.8
22	Anoka, Minn.	85,916	35,579	50,337	141.5
23	Suffolk, N.Y.	666,784	276,129	390,655	141.5
24	Pinellas, Fla.	374,665	159,249	215,416	135.3
25	Lee, Fla.	54,539	23,404	31,135	133.0
26	Curry, Oreg.	13,983	6,048	7,935	131.2
27	Orange, Fla.	263,540	114,950	148,590	129.3
28	Johnson, Kans.	143,792	62,783	81,009	129.0
29	Jefferson, Colo.	127,520	55,687	71,833	129.0
30	Okaloosa, Fla.	61,175	27,533	33,642	122.2
31	Prince William, Va.	50,164	22,612	27,552	121.8
32	Santa Clara, Calif.	642,315	290,547	351,768	121.1
33	Del Norte, Calif.	17,771	8,078	9,693	120.0
34	Macomb, Mich.	405,804	184,961	220,843	119.4
35	Arapahoe, Colo.	113,426	52,125	61,301	117.6
36	Martin, Fla.	16,932	7,807	9,125	116.9
37	Ector, Texas	90,995	42,102	48,893	116.1
38	Bucks, Pa.	308,567	144,620	163,947	113.4
39	Indian River, Fla.	25,309	11,872	13,437	113.2
40	South Norfolk, Va.1	22,035	10,434	11,601	111.2
41	Davis, Utah	64,760	30,867	33,893	109.8
42	Montgomery, Md.	340,928	164,401	176,527	107.4
43	Henrico, Va.	117,339	57,340	59,999	104.6
44	Seminole, Fla.	54,947	26,883	28,064	104.4
45	Du Page, Ill.	313,459	154,599	158,860	102.8
46	Clayton, Ga.	46,365	22,872	23,493	102.7
47	Meade, Ky.	18,938	9,422	9,516	101.0
48	Jefferson, I.a.	208,769	103,873	104,896	101.0
49	Maricopa, Ariz.	663,510	331,770	331,740	100.0

¹Independent city.
²Hampton city and Elizabeth City County consolidated since 1950. 1950 population is for Hampton city only.
³ Newport News city and Warwick County consolidated since 1950. 1950 population is for Newport News city only.

The minor civil divisions which have been used traditionally for the presentation of statistics for the component parts of counties represent political or administrative subdivisions set up by the States, In addition to the county divisions shown by the Bureau, there are thousands of school, taxation, election, and other units for which separate census figures are not published. Where more than one type of primary division exists in a county, the Bureau of the Census uses the more stable divisions, so as to provide comparable statistics from decade to decade, insofar as possible.

Among the States where minor civil divisions are still recognized, there is a considerable variety of types. Although civil and judicial townships are the most frequent type of minor civil division, there are also beats, election districts, magisterial districts, towns, and gores. In some instances, as Is discussed more fully below, none of the systems of subdivisions is adequate, and census county divisions have been substituted for them, The numbers and types of minor civil divisions in each State are shown in table 26.

For purposes of presenting census statistics, counties in 18 States have been subdivided into statistical areas, which are called "census county divisions" (CCD's). These divisions are used instead of the election precincts, townships, or other minor civil divisions for which population statistics were previously reported. These changes were made because the boundaries of the minor civil divisions observed in previous censuses changed frequently or were indefinite. Where the boundaries changed frequently, comparison of the data from one census to another was impeded and the statistics for the areas were of limited value. Enumerators had difficulty in locating boundaries and in obtaining an accurate count of the population where the boundaries were Indefinite, did not follow physical features, or were not well known by many of the inhabitants because the areas had lost most, if not all, of their local functions.

Census county divisions were established in the State of Washington for use in the 1950 Census. Between 1950 and 1960, they were established in 17 additional States, including 10 States in the West-Arizona, California, Colorado, Hawaii, Idaho, Montana, New Mexico, Oregon, Utah, and Wyoming-and 7 States in the South-Alabama, Florida, Georgia, Kentucky, South Carolina, Tennessee, and Texas.

The census county divisions were defined with boundaries that seldom require change and that can be easily located. The boundaries normally follow physical features, such as roads, highways, trails, railroads, power lines, streams, and ridges. The use of survey lines was limited. The larger incorporated places are recognized as separate divisions, even though their boundaries may change as the result of annexations. Cities with 10,000 inhabitants or more generally are separate divisions. In addition, some incorporated places with as few as 2,500 inhabitants may be separate divisions. Where an unincorporated enclave exists within a city, it is included in the same census county division as the city. In establishing census county divisions, consideration was given to the trade or service areas of principal settlements and in some cases to major land use or physiographic differences.

In areas with census tracts, each census county division is a census tract or group of tracts, or the combination of two census county divisions represents one census tract.

In the State of Washington, some revisions in the census county divisions recognized in 1950 were made in the metropolitan counties in order to coordinate the divisions with the expanded system of census tracts.

Bach census county division has a name which is ordinarily the name of the principal place located within it, except in the State of Washington, where most county divisions are numbered rather than named. The boundaries of census county divisions were reviewed with the officials in each county and various State agencies and were approved by the governors of the States or their representatives.

In addition to the 6,558 census county divisions, 31,309 minor civil divisions were recognized in the 1960 Census. Of these latter, nearly two-thirds (19,865) were townships, the next largest group were independent municipalities (4,494), and the third largest group, towns in the New England States, New York, and Wisconsin. Dependent municipalities are subdivisions of the minor civil divisions in which they are found.

In the 1960 Census, survey townships in the sparsely settled parts of Michigan, Nebraska, North and South Dakota, Minnesota, Maine, and New Hampshire were not separately identified. The population of these areas is shown as a residual for unorganized territory in the counties involved. In Alaska there are no subdivisions of the election districts (the county equivalents).

The term "place" as used in reports of the decennial censuses refers to a concentration of population regardless of the existence of legally prescribed limits, powers, or functions. Most of the places listed are incorporated as cities, towns, villages, or boroughs, however. In addition, the larger unincorporated places outside the urbanized areas were delineated and those with a population of 1,000 or more are presented in the same manner, as incorporated places of equal size. Bach unincorporated place possesses a definite nucleus of residences and has Its boundaries drawn so as to include, if feasible, all the surrounding closely settled area. Unincorporated places are shown within urbanized areas if they have 10,000 inhabitants or more and if there was an expression of local interest in their recognition. The towns in New England and townships in New Jersey and Pennsylvania recognized as urban are also counted as places, as is Arlington County, Va.

Political units recognized as incorporated places in the reports of the decennial censuses are those which are incorporated as cities, boroughs, towns, and villages with the exception that towns are not recognized as incorporated places In the New England States, New York, and Wisconsin. The towns in these States are minor civil divisions similar to the townships found in other States and not necessarily thickly settled centers of population such as the cities, boroughs, towns, and villages in other States. Similarly, in New Jersey and Pennsylvania, Where some townships possess powers and functions similar to those of incorporated places, the townships are not classified as "incorporated places." Thus some minor civil divisions which are "incorporated" in one legal sense of the word are not regarded by the Census Bureau as "incorporated places." Without this restriction all of the towns in the New England States, New York, and Wisconsin and the townships in New Jersey and Pennsylvania would have to be counted as incorporated places without any consideration of the nature of population settlement. A number of towns and townships in the New England States, New Jersey, and Pennsylvania do qualify, however, as urban towns or townships and in other towns and townships the densely settled portions are recognized as unincorporated places or as parts of an urban fringe.

As In the 1950 Census, the Bureau has delineated, in advance of enumeration, boundaries for densely settled population centers without corporate limits. Population data for 1950 are shown only for those unincorporated places which had the same name in both 1950 and 1960. Of course, the boundaries of many such places have changed as the communities have grown. All places in Hawaii except Hilo and Honolulu, and all places in Puerto Rico, are unincorporated.

The count of urban places in 1960 includes all incorporated and unincorporated places of 2,500 inhabitants or more and the towns, townships, and counties classified as urban. Under the "previous" urban definition, places of 2,500 or" more and the areas urban under special rules were urban places.

In most States the incorporated places form subdivisions of the minor civil divisions in which they are located. In other States, however, all or some of the incorporated places are themselves also minor civil divisions. St. Louis, Baltimore, and 32 cities in Virginia are independent of any county organization. In a number of instances such as Philadelphia, New Orleans, and San Francisco, the incorporated place is coextensive with the county in which it is located. New York City, on the other hand, is made up of five counties. An incorporated place may be located in two or more minor civil divisions or in two or more counties. Since, however, incorporated places are chartered by a State no place can be located in two States, and adjoining places of the same name in two States are quite separate incorporations.

The numbers and population of all places of various types are presented in table K. The 18,088 incorporated places of 1960 had a combined population of about 116 million, or 65 percent of the total population. The 1,570 unincorporated places of 1,000 or more had a population of about 6.5 million, and the 125 urban towns or townships and 1 urban county, a population of about 3.3 million. Classified by size, incorporated places run the entire gamut from small to large. In 1960, there were 2,455 such places with a population of less than 200; and all 51 of the places of 250,000 inhabitants or more were incorporated places. Unincorporated places are arbitrarily cut off at the lower end of the size distribution at 1,000 and are heavily concentrated in the range from 1,000 to 5,000, although there was one unincorporated place of slightly more than 100,000. There are, of course, a great many unincorporated places with fewer than 1,000 inhabitants. Similarly, the definition of urban towns and townships places an arbitrary lower limit on their size. Places of this type tended toward concentration within the range from 10,000 to 50,000.

Of the incorporated places, 1,214 were boroughs, 5,911 were cities, 6,085 were towns, find 4,878 were villages. Illinois had the largest number of Incorporated places--1,247, If we exclude the District of Columbia and Hawaii, where Hilo and Honolulu are considered cities, the smallest number of Incorporated places in any one State Is the eight In Rhode Island, The number and types of Incorporated places by States are shown in table 27.

Between 1950 and 1960, a number of shifts took place in the rank of the leading cities (table 29). Among the 10 most populous cities, 5 kept their 1950 ranking. The cities which ranked first and second in 1950-New York and Chicago-retained their positions in 1960 as did Detroit, Baltimore, and Washington, which occupied fifth, sixth, and ninth place, respectively. Los Angeles replaced Philadelphia as the third most populous city. Houston became one of the 10 most populous cities for the first time, reaching the seventh position and replacing Cleveland, which now ranks 8i the eighth most populous city. St. Louis dropped from eight to tenth place; and Boston, which occupied the tenth position in 1950, dropped to thirteenth in 1960. Among the top fifty cities in 1960, the greatest gains in rank were made by Phoenix, which rose to twenty-ninth place from ninety-ninth, in 1950, and by Tampa, which rose to forty-eighth place from eighty-fifth place.

Table K. Population in Groups of Incorporated and Unincorporated Places Classified According to Size: 1960 and 1950
[Urban towns and townships were not recognized in 1960]
1960

Size of place	1960						1950
	Incorporated places		Unincorporated places		Urban towns and towships1		Incorporated places		Unincorporated places
	Number	Population	Number	Population	Number	Population	Number	Population	Number	Population
Total	18,088	115,910,866	1,576	6,583,549	126	3,313,559	17,145	96,108,257	1,470	3,946,768
Places 1,000,000 or more	5	17,484,059	…	…	…	…	5	17,404,450	…	…
Places 500,000 to 1,000,000	16	11,110,991	…	…	…	…	13	9,186,946	…	…
Places 250,000 to 500,000	30	10,765,881	…	…	…	…	23	8,241,560	…	…
Places 100,000 to 250,000	79	11,384,755	7	104,270	1	163,401	65	9,478,662	1	248,034
Places 50,000 to 100,000	180	12,511,961	9	585,104	12	738,837	126	8,090,828	…	…
Places 25,000 to 50,000	366	12,720,406	26	858,459	40	1,371,747	249	8,710,867	4	124,052
Places 10,000 to 25,000	978	15,061,679	101	1,565,850	55	940,757	753	11,526,409	26	351,350
Places 5,000 to 10,000	1,282	9,030,786	104	688,135	8	60,793	1,096	7,580,541	88	606,095
Places 2,500 to 5,000	1,763	6,237,739	379	1,304,265	10	38,024	1,557	5,512,970	301	1,016,041
Places 1,000 to 2,500	3,515	5,570,178	956	1,477,566	…	…	3,415	5,894,860	1,050	1,601,196
Places under 1,000	9,874	4,032,430	…	…	…	…	9,843	4,134,661	…	…

¹Includes one urban county (Arlington, Va.) with a population of 163,401.

The largest drops in rank were experienced by Jersey City, which fell from thirty-seventh place in 1950 to forty-seventh in 1960, and by Newark, which fell from twenty-first to thirtieth place during this period.

Statistics for cities of 25,000 or more that increased by more than 100 percent in the decade 1950 to 1960 are presented in table L. Many of these cities annexed large areas during the decade.

Table L. Cities of 25,000 or More in 1950 Which Increased by 100 Percent or More between 1950 and 1960

Rank according to percent increase	Cit	1960	1950	Increase, 1950 to 1960		1960 population in territory annexed between 1950 and 1960
				Number	Percent	Number	As percent of the 1950 to 19601 increase
1	Tucson, Ariz.	212,802	45,454	167,438	368.4	167,112	99.8
2	Phoenix, Ariz.	439,170	106,818	332,352	311.1	332,398	100.0
3	Parma, Ohio	82,845	28,807	53,948	186.7	…	…
4	Odessa, Texas	80,338	29,495	50,848	172.4	51,171	100.6
5	Newport News, Va.	113,662	42,358	71,304	168.3	71,429	100.2
6	San Leandro, Calif.	65,692	27,542	38,420	139.5	37,766	98.3
7	Vallejo, Calif.	60,877	26,038	34,839	133.8	37,600	107.9
8	Fort Lauderdale, Fla.	83,648	36,328	47,320	130.3	6,640	18.3
9	Tampa, Fla.	274,970	124,681	150,289	120.5	140,331	93.4
10	Santa Ana, Calif.	100,350	45,533	54,817	120.4	29,027	53.0
11	San Jose, Calif.	204,190	95,280	108,916	114.3	99,380	91.2
12	El Paso, Texas	270,687	130,485	148,202	112.0	124,155	84.9
13	Albuquerqus, N. Mex.	201,180	96,815	104,374	10.78	23,646	22.7
14	Palo Alto, Calif.	52,287	25,475	26,812	105.2	17,683	66.0

¹A figure grantor than 100.0 indicates a decline in population in 1050 territory of city.

The population figure for an incorporated place at earlier censuses applies to the area of the place at the time of the given census. Hence, the indicated change in population reflects the effect of any annexations or detachments. In order to permit the analysis of the relative importance of population growth within old boundaries and of population added by annexation, separate counts of the population in annexed areas were made for the first time in the 1960 Census. The figures are presented in table 9 of the State reports. There were 8.8 million persons in 1960 living in territory annexed between 1950 and 1960 by incorporated places of 2,500 or more in 1950. Here (table M) statistics on annexations are presented for cities of 25,000 or more which had a population of 10,000 or more in the area annexed since 1950. An additional 57 cities of this size had between 5,000 and 10,000 persons living in areas annexed between 1950 and 1960, Tables P and Q give some indication of the relation between annexation and the rates of change in the population of the central cities of SMSA's during the decade.

Detachments from cities are far less frequent than annexations, and, for the most part, involve smaller areas. Information on the population residing in the detached areas was obtained for three cities. The largest number of persons involved was the 5,490 persons living in the area detached from Tuskegee, Ala. The numbers in the areas detached from White Bear Lake, Minn., and Brownwood, Texas, were 880 and 976, respectively. The detachment from Tuskegee, however, was subsequently nullified by judicial action.

It has long been recognized that for many types of analysis it is necessary to consider as a unit the entire population in and around a city the activities of which form an integrated economic and social system. Prior to the 1950 Census, areas of this type had been defined in somewhat different ways for different purposes and by various agencies. Leading examples were the metropolitan districts of the Census of Population, the industrial areas of the Census of Manufactures, and the labor market areas of the Bureau of Employment Security.. To permit all Federal statistical agencies to utilize the same areas for the publication of general-purpose statistics, the Bureau of the Budget has established "standard metropolitan statistical areas" (SMSA's). Every city of 50,000 inhabitants or more according to the 1960 Census of Population is included in an SMSA.

The definitions and titles of standard metropolitan statistical areas are established by the Bureau of the Budget with the advice of the Federal Committee on Standard Metropolitan Statistical Areas. This Committee is composed of representatives of the major statistical agencies of the Federal Government. The criteria used by the Bureau of the Budget in establishing the SMSA's are presented below. (See the Bureau of the Budget publication Standard Metropolitan Statistical Areas, U.S. Government Printing Office, Washington 25, D.C., 1961).

The definition of an individual standard metropolitan statistical area involves two considerations: first, a city or cities of specified population to constitute the central city and to identify the county in which it is located as the central county; and, second, economic and social relationships with contiguous counties which are metropolitan in character, so that the periphery of the specific metropolitan area may be determined.⁶ Standard metropolitan statistical areas may cross State lines.

Table M. Cities of 25,000 or More in 1950 Which Had 10,000 Inhabitants or More Living in Territory Annexed Between 1950 and 1960

Rank	City	Population living in annexed territory in 1960
		Number	Percent of 1960 population of city
1	Phoenix, Ariz	332,398	75.7
2	Houston, Tex	251,198	26.8
3	Dallas, Tox	192,707	28.4
4	Atlanta, Ga	171,467	35.2
5	Tucson, Ariz	167,112	78.5
6	Tampa, Fla	140,331	51.0
7	San Antonio, Tex	139,492	28.7
8	El Paso, Tex	124,155	44.9
9	Milwaukee, Wis	123,870	16.7
10	Tulsa, Okla	101,325	38.7
11	San Jose, Calif	99,380	48.7
12	Norfolk, Va	88,321	28.9
13	Seattle, Wash	86,079	15.5
14	Wichita, Kans	83,490	32.8
15	Columbus, Ohio	75,635	16.0
16	Newport News, Va.	71,420	62.8
17	Oklahoma City, Okla.	70,176	21.6
18	Memphis, Tenn	69,095	13.9
19	San Diego, Calif	65,843	11.5
20	Mobile, Ala	62,375	30.8
21	Louisville, Ky	62,229	15.9
22	Long Beach, Calif	59,159	17.2
23	Fort Worth, Tex	56,790	15.9
24	Charlotte, N.C	56,706	28.1
25	Sacramento, Calif	52,672	27.5
26	Odessa, Tex	51,171	63.7
27	Indianapolis, Ind	47,449	10.0
28	Wichita Fails, Tex.	46,122	45.3
29	Amarillo, Tex	45,383	32.0
30	Fresno, Oalif	44,567	33.3
31	Abilene, Tex	43,930	48.6
32	Corpus Ohrlsti, Tex.	43,638	26.0
33	Columbus, Ga	43,459	37.2
34	Topeka, Kans	42,029	35.2
35	Kansas City, Mo	42,018	8.8
36	Omaha, Nebr	40,216	13.3
37	Denver, Colo	38,283	7.8
38	San Leandro, Calif	37,766	57.3
39	Vallejo, Calif	37,600	61.8
40	Austin, Tex	37,353	20.0
41	Portsmouth, Va	36,719	32.0
42	Greensboro, N.C	36,117	30.2
43	Shreveport, La	35,241	21.4
44	Lubbock, Tex	34,389	26.7
45	Jackson, Miss	33,664	23.3
46	Dayton, Ohio	32,772	12.5
47	Kalamazoo, Mich	29,976	35.5
48	Springfield, Mo	29,801	31.1
49	Santa Ana, Calif	29,027	28.0
50	Raleigh, N.C	28,536	30.4
51	Madison, Wis	27,899	22.0
52	Fort Wayne, Ind	26,908	16.6
53	Evansville, Ind	25,525	18.0
54	Savannah, Ga	25,163	16.9
55	Rockford, Ill.	24,849	19.6
56	West Allis, Wis	24,339	35.7
57	Pueblo, Colo	24,136	26.5
58	Bakersfield, Calif	23,976	42.2
59	Billings, Mont	23,865	45.2
60	Albuquerque, N. Mex.	23,646	11.8
61	Colorado Springs, Colo.	22,703	32.3
62	Wauwatosa, Wis	20,386	35.8
63	Tallahassee, Fla	20,342	42.2
64	Alexandria, Va	20,159	22.1
65	Winston-Salem, N.C.	20,003	18.0
66	Glendale, Calif.	19,478	16.3
67	Toledo, Ohio	19,171	6.0
68	Des Moines, Iowa	18,937	9.1
69	Stockton, Calif	18,810	21.8
70	Charleston, W. Va.	18,685	21.8
71	Orlando, Fla	18,501	21.0
72	Lawton, Okla	18,262	29.6
73	Palo Alto, Calif	17,683	33.8
74	Albany, Ga	17,569	31.4
75	Ann Arbor, Mich	16,699	24.8
76	High Point, N.C	16,115	26.0
77	Independence, Mo	15,413	24.7
78	Norwich, Conn	15,409	40.0
79	Terre Haute, Ind	15,256	21.0
80	Waco, Tex	15,132	15.5
81	Parkersburg, W. Va.	14,457	32.3
82	Columbia, S.C.	14,184	14.6
83	Decatur, Ill.	15,026	18.0
84	Montgomery, Ala	13,757	10.2
85	Danville, Va	13,482	28.9
86	Little Rock, Ark	13,219	12.3
87	Hamilton, Ohio	13,171	18.2
88	Pensacola, Fla	13,143	23.2
89	San Bernardino, Calif.	12,803	13.9
90	Birmingham, Ala	12,714	3.7
91	Owensboro, Ky.	12,588	29.6
92	Salina, Kans	12,582	29.1
93	Great Falls, Mont	11,957	21.6
94	Lansing, Mich	11,766	10.9
95	New Albany, Ind	11,339	30.0
96	Portland, Ores	11,013	3.0
97	Tuscaloosa, Ala	10,988	17.3
98	Tyler, Tex	10,893	21.3
99	Reno, Nev	10,629	20.7
100	Jollet, III	10,390	15.6
101	Eugene, Oreg	10,381	20.4
102	Ashevilie, N.C	10,109	16.8
103	Appleton, Wis	10,040	20.7

The criteria for population relate to a city or cities of specified size according to the 1960 Census of Population.

1. Each standard metropolitan statistical area must include at least:
a. One city with 50,000 inhabitants or more, or
b. Two cities having contiguous boundaries and constituting, for general economic and social purposes, a single community with a combined population of at least 50,000, the smaller of which must have a population of at least 15,000.
2. If two or more adjacent counties each have a city of 50,000 inhabitants or more (or twin cities under lb) and the cities are within 20 miles of each other (city limits to city limits), they will be included In the same area unless there is definite evidence that the two cities are not economically and socially integrated.

The criteria of metropolitan character relate primarily to the attributes of the contiguous county as a place of work or as a home for a concentration of nonagricultural workers.
3. At least 75 percent of the labor force of the county must be in the nonagricultural labor force. ⁷
4. In addition to criterion 3, the county must meet at least one of the following conditions:
a. It must have 50 percent or more of its population living in contiguous minor civil divisions⁸ with a density of at least 150 persons per square mile, in an unbroken chain of minor civil divisions with such density radiating from a central city in the area.
b. The number of nonagricultural workers employed in the county must equal at least 10 percent of the number of nonagricultural workers employed in the county containing the largest city in the area, or the count/ must be the place of employment of 10,000 nonagricultural workers.
c. The nonagricultural labor force living in the county must equal at least 10 percent of the number in the nonagricultural labor force living in the county containing the largest city in the area, or the county must be the place of residence of a nonagricultural labor force of 10,000.
5. In New England, the city and town are administratively more important than the county, and data are compiled locally for such minor civil divisions. Here, towns and cities are the units used in defining standard metropolitan statistical areas. In New England, because smaller units are used and more restricted areas result, a population density criterion of at least 100 persons per square mile is used as the measure of metropolitan character.

The criteria of integration relate primarily to the extent of economic and social communication between the outlying counties and central county.
6. A county is regarded as integrated with the county or counties containing the central cities of the area if either of the following criteria is met:
a. 15 percent of the workers living in the county work in the county or counties containing central cities of the area, or
b. 25 percent of those working in the county live in the county or counties containing central cities of the area.
Only where data for criteria 6a and 6b are not conclusive are other related types of information used as necessary. This information includes such items as average telephone calls per subscriber per month from the county to the county containing central cities of the area; percent of the population in the county located in the central city telephone exchange area; newspaper circulation reports prepared by the Audit Bureau of Circulation; analysis of charge accounts in retail stores of central cities to determine the extent of their use by residents of the contiguous county; delivery service practices of retail stores in central cities; official traffic counts; the extent of public transportation facilities in operation between central cities and communities in the contiguous county; and the extent to which local planning groups and other civic organizations operate jointly.

The criteria for titles relate primarily to the size and number of central cities.
7. The complete title of an SMSA identifies the central city or cities and the State or States in which the SMSA is located:
a. The name of the standard metropolitan statistical area includes that of the largest city.
b. The addition of up to two city names may be made in the area title, on the basis and in the order of the following criteria:
(1) The additional city has at least 250,000 inhabitants.
(2) The additional city has a population of one-third or more of that of the largest city and a minimum population of 25,000, except that both city names are used in those instances where cities qualify under criterion 1b. (A city which qualified as a secondary central city in 1950 but which does not qualify in 1960 has been temporarily retained as a central city.)
c. In addition to city names, the area title contains the name of the State or States in which the area is located.

In the 1950 Census reports, data were presented for standard metropolitan areas (SMA's) and in several earlier censuses a somewhat similar type of area called the "metropolitan district" was used. In 1958, the criteria for delineating SMA's were revised by the Bureau of the Budget, and, in 1959, the areas were designated as standard metropolitan statistical areas. The comparative figures shown here for 1950 apply to the SMSA as defined in 1960.

In view of the special importance of the metropolitan complexes around New York and Chicago, the Nation's largest cities, several contiguous SMSA's and additional counties that do not appear to meet the formal integration criteria but do have strong Interrelationships of other kinds have been combined into the New York-Northeastern New Jersey and the Chicago-Northwestern Indiana Standard Consolidated Areas, respectively. The former is identical with the New York - Northeastern New Jersey SMA of 1950, and the latter corresponds roughly to the Chicago SMA of 1950 (two more counties having been added).

The urbanized area can be characterized as the physical city as distinguished from both the legal city and the metropolitan community. In most cases urbanized areas are smaller than SMSA's and are contained in SMSA's. However, in a few instances, the fact that the boundaries of SMSA's are determined by county lines, and those of urbanized areas by the pattern of urban growth, means that there are small segments of urbanized areas which lie outside SMSA's. In general then, urbanized areas represent the thickly settled portions of the SMSA's. Because of discontinuities in land settlement, there are also some cases in which a single SMSA contains several urbanized areas. As the foregoing discussion suggests, the population in urbanized areas, but outside SMSA's, is relatively small as compared with the population in SMSA's outside urbanized areas. This, slightly less than 1 percent of the population of urbanized areas was in areas outside SMSA's (table N). The population of SMSA's outside urbanized areas, however, constitutes a larger proportion of the total population of SMSA's (15.8 percent). This situation reflects, as might be expected, the existence of considerable rural area in metropolitan counties, particularly outside the Northeast.

Table N. Population in and Outside Urbanized Areas and Standard Metropolitan Statistical Areas: 1960

Location	Population	In standard metropolitan statistical areas	Outside standard metropolitan statistical areas
Total	179,323,175	112,885,178	66,437,997
In urbanized areas	95,848,487	95,076,272	772,215
Outside urbanized areas	83,474,688	17,808,906	65,665,782

There are three standard metropolitan statistical areas in Puerto Rico-Mayaguez, Ponce, and San Juan. The largest of these, San Juan, had a population of 588,805, slightly larger than the Rochester area and slightly less than the Jersey City area.

Table O. Population in Groups or Standard Metropolitan Statistical Areas Classified According to Size: 1940 to 1960
[Data relate to areas as defined for 1960]

Size of area	Number of areas			Population
	1960	1950	1940	1960	1950	1940
Total	212	212	212	112,885,178	89,316,903	72,834,468
3,000,000 or more	5	5	3	21,763,499	25,788,967	16,476,197
1,000,000 to 3,000,000	19	10	9	29,818,571	16,627,603	16,210,036
500,000 to 1,000,000	29	21	16	19,214,817	14,439,987	11,058,897
250,000 to 250,000	48	44	36	15,829,087	15,209,376	12,007,871
100,000 to 250,000	89	89	76	14,497,817	14,045,736	12,077,950
Under 100,000	22	43	72	1,761,407	3,205,234	5,005,527

The population of 112.9 million in standard metropolitan statistical areas (SMSA's) represents an increase of 23.8 million, or 26.4 percent, over the 89.3 million inhabitants of these areas In 1950 (table P). SMSA's stand in marked contrast with the remainder of the country in which the rate of increase was only 7.1 percent.

The 5.6 million increase in the population of central cities to a total of 58.0 million persons in 1960, represented a 10.8 percent increase over the 1950 population, a rate of growth considerably less than that for the country as a whole. In the outlying parts of the SMSA's, however, the population increased by 48.5 percent between 1950 and 1960, growing from 36.9 million persons to 54,9 million. Of the increase of about 28 million for the United States during the decade, about 84 percent occurred in SMSA's and nearly two-thirds occurred outside the central cities.

The metropolitan-nonmetropolitan pattern of increase varied considerably among the regions. The population in and outside metropolitan areas of the Northeast increased at about the same rate (18.0 and 13.6 respectively), that of central cities decreased by about 3 percent, and that of the suburban ring Increased by more than one-third. In the North Central States, the rate of Increase in metropolitan areas was over three times that outside metropolitan areas (23.5 vs. 6.6 percent). Central cities showed a modest increase of 4 percent, and the suburban ring increased by 56 percent. In the South, the population of standard metropolitan statistical areas increased at a rate 13 times as great as the population living outside such areas (36.2 vs. 2.7 percent) ; that of central cities increased by more than one Quarter, and that of the suburban ring by almost one-half. In the West, the population of the metropolitan areas increased at more than twice the rate of the population of nonmetropolitan areas (49 vs. 19 percent). The rate of increase for central cities was about 31 percent and that of the outlying area about 66 percent.

Table P. Population of Standard Metropolitan Statistical Areas, by Regions, for the United States: 1960 and 1950
[Minus sign (-) denotes decrease]

Region and component parts of SMSA	1960	1950	Change, 1950 to 1960
			Total		Based on 1950 limits of central cities		From annexations
			Number	Percent	Number	Percent	Number	Percent
United States
In SMSA's	112,885,178	89,316,903	23,568,275	26.4	23,568,275	26.4	…	…
Central cities	58,004,384	52,371,379	5,632,955	10.8	767,209	1.5	4,851,483	9.3
Outside central cities	54,880,844	36,945,524	17,935,320	48.5	22,801,066	61.7	-4,851,483	-13.1
Northeast
In SMSA's	35,346,505	31,267,169	4,079,336	13.0	4,079,336	13.0	…	…
Central cities	17,321,781	17,881,490	-559,759	-3.1	-594,078	-3.8	20,115	0.1
Outside central cities	18,024,774	13,385,679	4,639,095	34.7	4,678,414	35.0	-20,115	-0.2
North Central
In SMSA's	30,959,961	25,074,674	5,885,287	23.5	5,885,287	23.5	…	…
Central cities	16,510,746	15,836,656	674,090	4.3	-257,583	-1.6	931,673	5.9
Outside central cities	14,449,218	9,238,018	5,211,197	56.4	6,142,870	66.5	-931,673	-10.1
South
In SMSA's	26,447,395	19,417,751	7,029,644	36.2	7,029,644	36.2	…	…
Central cities	15,061,777	11,720,843	3,340,934	28.5	615,801	5.3	2,725,133	23.3
Outside central cities	11,385,618	7,696,908	3,688,710	47.9	6,413,843	83.3	-2,725,133	-35.4
West
In SMSA's	20,131,317	13,557,309	6,574,008	48.5	6,574,008	48.5	…	…
Central cities	9,110,080	6,932,390	2,177,690	31.4	1,003,069	14.5	1,174,562	16.9
Outside central cities	11,021,237	6,624,919	4,396,318	66.4	5,570,939	84.1	-1,174,562	-17.7

The variations in rates of increase among SMSA's of different sizes were less extensive (table Q). The population Increased most rapidly in those SMSA's that ranged in size from 500,000 to 1,000,000, where the rate of increase was 36.0 percent. Among the SMSA's of other size classes, the rate of population growth ranged only from a low of 23,2 percent for those areas of 3,000,000 or more to 25.8 percent for areas of 100,000 to 250,000. The relation between growth rates of central cities and outlying areas was clearly associated with the size of the SMSA. In the five SMSA's of 3,000,000 or more, the gain In central cities was only 1 percent whereas the increase in the suburban ring was 71 percent. Progressively, as size declined, the rate of growth of central cities increased In relation to that of the ring, so that in SMSA's of less than 100,000, the rate for the central cities (29 percent) exceeded that for the ring (11 percent).
Annexations of territory from the outlying areas by central cities considerably affected the rates of population change during the decade within the two components of SMSA's (table P). Of the increase of 10.8 percent in the population of central cities, 9,3 percent resulted from annexations, and only 1.5 percent from the increase of population within the 1950 city limits. The 58.0 million persons in central cities in 1960 included 4.9 million living in sections that had been annexed to these cities since the previous census. Large differences existed in the relative contributions resulting from annexations among the central cities of SMSA's of the various size classes and regions. The smallest change In central cities from annexations occurred In metropolitan areas of 3,000,000 or more, where these gains amounted to only 0.4 percent, compared to an increase of 0.6 percent through growth within the 1950 city limits. In SMSA's of 1,000,000 to 3,000,000, the population within the 1950 boundaries of central cities declined by 2.2 percent, but annexations added 7.8 percent to the 1950 total. In each of the size classes of SMSA's with fewer than one million inhabitants, more than two-thirds of the increase in the population of central cities resulted from annexations.

In the North Central States and in the Northeast, the population within the 1950 limits of central cities declined by 2 to 3 percent; but in the former region, annexations of territory containing nearly one million persons in 1960 enabled the central cities to show an increase of 4 percent. The greatest numerical and proportionate increases to central cities from annexations occurred in the South and West; in the South this amounted to about four-fifths of the increase experienced by central cities between 1950 and 1960 (28.8 percent of the 28.5 percent) and in the West, over one-half (16.9 percent of the 31.4 percent).
Of the 212 standard metropolitan statistical areas, 204 gained population between 1950 and 1900, and 8 lost population (table 31). The areas with population losses were Altoona, Jersey City, Johnstown, St. Joseph, Scranton, Texarkana, Wheeling, and Wilkes-Barre-Hazleton. Six of these areas-St. Joseph and Texarkana were the exceptions-had also lost population in the previous decade. In each of the declining areas, except St. Joseph and Texarkana, the central cities also lost population (table 83). The two gains in central cities resulted from annexations of outlying territory; the population within the 1950 city limits declined. Of the 204 SMSA's that gained population, 138, or about two-thirds, had increases of 20 percent or more, and 82, or slightly less than three-tenths of all metropolitan areas, had increases of one-third or more. One area, that of Fort Lauderdale-Hollywood, almost quadrupled in population, with an Increase of 297.9 percent. Six other areas, those of Las Vegas, Midland, Orlando, San Jose, Odessa, and Phoenix, doubled in population, experiencing Increases ranging from 100.0 to 163.0 percent.

Table Q. Population of Standard Metropolitan Statistical Areas, by Size of Area: 1960 and 1950
[Minus sign (-) denotes decrease]

Size in 1960 and component parts of SMSA	1960	1950	Change, 1950 to 1960
			Total		Based on 1950 limits of central cities		From annexations
			Number	Percent	Number	Percent	Number	Percent
All Sizes
In SMSA's	112,885,178	89,316,903	23,568,275	26.4	23,568,275	26.4	…	…
Central cities	58,004,384	52,371,379	5,632,955	10.8	767,209	1.5	4,851,483	9.3
Outside central cities	54,880,844	36,945,524	17,935,320	48.5	22,801,066	61.7	-4,851,483	-13.1
3,000,000 or more
In SMSA's	31,763,499	25,788,967	5,974,532	23.2	5,974,532	23.2	…	…
Central cities	17,828,227	17,655,217	173,010	1.0	99,318	0.6	73,692	0.4
Outside central cities	13,935,272	8,133,750	5,801,522	71.3	5,875,214	72.2	-73,692	-0.9
1,000,000 to 3,000,000
In SMSA's	29,818,571	23,858,113	5,960,458	25.0	5,960,458	25.0	…	…
Central cities	12,707,503	12,037,125	670,378	5.6	-270,275	-2.2	940,653	7.8
Outside central cities	17,111,068	11,820,988	5,290,080	44.8	6,230,733	52.7	-940,653	-8.0
500,000 to 1,000,000
In SMSA's	19,214,817	14,125,628	5,089,189	36.0	5,089,189	36.0	…	…
Central cities	10,126,684	8,340,585	1,786,099	21.4	396,636	4.8	1,389,463	16.7
Outside central cities	9,088,133	5,785,043	3,303,090	57.1	4,692,553	81.1	-1,389,463	-24.0
250,000 to 500,000
In SMSA's	15,829,067	12,603,137	3,225,930	25.6	3,225,930	25.6	…	…
Central cities	7,750,597	6,671,381	1,079,216	16.2	146,234	2.2	932,982	14.0
Outside central cities	8,078,470	5,931,756	2,146,714	36.2	3,079,696	51.9	-932,982	-15.7
100,000 to 250,000
In SMSA's	14,497,817	11,525,685	2,972,132	25.8	2,972,132	25.8	…	…
Central cities	8,235,553	6,617,624	1,617,929	24.4	305,082	4.6	1,298,584	19.6
Outside central cities	6,262,264	4,908,061	1,354,203	27.6	2,667,050	54.5	-1,298,584	-26.5
Under 100,000
In SMSA's	1,761,407	1,415,373	346,034	24.4	346,034	24.4	…	…
Central cities	1,355,770	1,049,447	306,323	29.2	90,214	8.6	216,109	20.1
Outside central cities	405,637	365,926	39,711	10.9	255,820	69.9	-216,109	59.8

Table R. Population or States by Metropolitan-Nonmetropolitan Residence: 1960 and 1950
[Figures relate to arena as defined for 1960. Minus sign (-) denotes decrease]

State	1960		1950		Percent increase, 1950 to 1960
	In SMSA's	Outside SMSA's	In SMSA's	Outside SMSA's	In SMSA's	Outside SMSA's
United States	112,885,178	66,437,997	89,316,908	62,008,895	26.4	7.1
Alabama	1,488,101	1,778,639	1,230,249	1,881,494	21.0	-2.9
Alaska	…	226,167	…	128,648	…	75.8
Arizona	929,170	372,991	472,986	276,601	96.4	34.8
Arkansas	341,351	1,444,921	293,501	1,616,010	16.3	-10.6
California	13,590,821	2,126,383	8,988,655	1,597,568	51.2	33.1
Colorado	1,191,882	562,115	776,839	548,250	53.4	2.5
Connecticut	1,966,427	568,807	1,576,688	430,592	24.7	32.1
Delaware	307,446	138,846	218,879	99,208	40.5	40.0
District of Columbia	763,956	…	802,178	…	-4.8	…
Florida	3,246,826	1,704,734	1,679,970	1,091,335	93.3	56.2
Georgia	1,814,069	2,129,047	1,334,381	2,110,197	35.9	0.9
Hawaii	500,409	132,363	353,020	146,774	41.8	-9.8
Idaho	…	667,191	…	588,637	…	13.3
Illinois	7,754,932	2,326,226	6,439,062	2,278,114	20.4	2.3
Indiana	2,241,307	2,421,191	1,796,904	2,137,820	24.7	13.3
Iowa	915,762	1,841,775	776,366	1,844,707	18.0	-0.2
Kansas	813,804	1,364,807	555,809	1,349,490	46.4	1.1
Kentucky	1,036,088	2,002,118	846,475	2,098,331	22.4	-4.6
Louisiana	1,627,157	1,629,865	1,224,675	1,458,841	32.9	11.7
Maine	190,950	778,315	188,368	725,406	1.4	7.3
Maryland	2,425,340	675,348	1,763,982	579,019	37.5	16.6
Massachussetts	4,387,101	761,477	4,041,791	648,723	8.6	17.4
Michigan	5,720,692	2,102,502	4,552,370	1,819,396	25.7	15.6
Minnesota	1,752,698	1,661,166	1,387,478	1,595,005	26.3	4.1
Mississippi	187,045	1,991,096	142,164	2,086,750	31.6	-2.2
Missouri	2,499,968	1,819,845	2,118,891	1,835,762	18.0	-0.9
Montana	152,434	522,333	108,902	482,122	40.0	8.3
Nebraska	520,043	881,287	416,455	909,055	27.8	-8.1
Nevada	211,759	73,519	98,494	61,589	115.0	19.4
New Hampshire	107,637	499,284	95,257	437,985	18.0	14.0
New Jersey	4,787,604	1,279,178	3,986,569	848,760	20.1	50.7
New Mexico	262,199	688,824	145,673	535,514	80.0	28.6
New York	14,352,693	2,429,611	12,656,238	2,178,954	13.4	11.8
North Carolina	1,119,210	3,436,945	896,736	3,165,198	24.8	8.6
North Dakota	65,947	565,499	58,877	560,759	13.7	08.
Ohio	6,748,362	2,958,035	5,445,395	2,501,232	23.9	18.3
Oklahoma	1,021,610	1,306,674	775,504	1,457,847	31.7	-10.4
Oregon	890,978	877,709	745,298	776,043	19.5	13.1
Pennsylvania	8,813,274	2,506,092	8,024,682	2,473,830	9.8	1.3
Rhode Island	740,819	118,669	697,578	94,320	6.2	25.8
South Carolina	768,024	1,614,570	572,989	1,544,038	34.0	4.6
South Dakota	86,575	593,939	70,910	581,830	22.1	2.1
Tennessee	1,682,747	1,934,342	1,349,511	1,942,207	21.0	-0.4
Texas	6,072,706	3,508,971	4,267,442	3,443,752	42.3	1.8
Utah	600,770	289,857	440,126	248,738	36.5	16.5
Vermont	…	389,881	…	377,747	…	3.2
Virginia	2,020,626	1,946,323	1,462,898	1,855,782	38.1	4.9
Washington	1,800,946	1,052,269	1,427,316	951,647	26.2	10.6
West Virginia	575,137	1,285,284	556,217	1,449,335	3.4	-11.3
Wisconsin	1,828,871	2,122,906	1,458,157	1,978,418	25.6	7.3
Wyoming	…	330,066	…	290,529	…	13.6

In 1960, the population per square mile of land area for all of the 212 standard metropolitan statistical areas in the United States was 364 as compared with 51 in the country as a whole (table 34). There were 2 standard metropolitan statistical areas-Jersey City and New York-with more than 3,000 inhabitants per square mile. At the other end of the scale 13 areas-Bakersfield, Billings, Duluth-Superior, Eugene, Fargo- Moorhead, Great Falls, Laredo, Las Vegas, Pueblo, Reno, San Angelo, San Bernardino-Riverside-Ontario, and Tucson-had a population density of less than 50 per square mile. This extreme variation in density among standard metropolitan areas is an indication, of course, of the limitations of whole counties as a basis for defining such areas. The area of San Bernardino County, Calif., for example, is greater than that of any of the New England States except Maine and nearly 10 times that of the New York Standard Metropolitan Statistical Area. In short, in those parts of the country where counties are large, the use of counties yields only a very rough approximation to the genuinely metropolitan territory, although most of the population is contained in genuinely metropolitan territory.

There was also considerable variability in density among the central cities of standard metropolitan statistical areas. Among central cities, the number of persons per square mile ranged from 24,697 in New York to 680 in Lewiston-Auburn. For areas outside central cities, this figure ranged from 12,871 in the Jersey City Standard Metropolitan Statistical Area to 1 in the Laredo area.

State economic areas are relatively homogeneous subdivisions of States. They consist of single counties or groups of counties which have similar economic and social characteristics. The boundaries of these areas have been drawn in such a way that each State is subdivided into relatively few parts, with each part having certain significant characteristics which distinguishes it from adjoining areas.

The State economic areas were originally delineated for the 1950 Censuses. The grouping of the 3,103 counties or county equivalents in 1950 into State economic areas was the product of a special study sponsored by the Bureau of the Census in cooperation with the Bureau of Agricultural Economics and several State and private agencies. The delineation procedure was devised by Dr. Donald J. Bogue, then of the Scripps Foundation for Research in population Problems, on loan to the Bureau of the Census.⁹The 1960 set of State economic areas represents a limited revision of the 1950 areas. This revision takes into account changes in the definitions of standard metropolitan statistical areas, but no attempt was made to reexamine the original principles or to apply them to more recent data relating to homogeneity. In addition, State economic areas were delineated for Alaska and Hawaii for the first time. As a result of the revision, the number of areas was increased from 501 to 509. (In the reports of the 1950 Census of Population, combination of areas reduced the number of publication areas to 453.)

The combination of counties into State economic areas has been made for the entire country, and in this process the larger standard metropolitan statistical areas (those in 1960 with a central city of 50,000 or more and a total population of 100,000 or more) have been recognized as metropolitan State economic areas.¹⁰When a standard metropolitan statistical area is located in two or more States or economic subregions, each State part and each part in an economic subregion becomes a separate metropolitan State economic area. In New England this correspondence of State metropolitan, State economic areas and standard metropolitan statistical areas does not exist because State economic areas are composed of whole counties, whereas standard metropolitan statistical areas are built up from towns. Here a county with more than half its population in one or more standard metropolitan statistical areas is classified as a metropolitan State economic area if the county or a combination of counties containing the standard metropolitan statistical area or areas has 100,000 inhabitants or more. Of the State economic areas, 206 are metropolitan.

In the establishment of State economic areas, factors in addition to Industrial and commercial activities were taken into account. Demographic, climatic, physiographic, and cultural factors, as well as factors pertaining more directly to the production and exchange of agricultural and nonagricultural goods, were considered. The net result then is a set of areas, intermediate in size between States, on the one hand, and counties on the other, which are relatively homogeneous with respect to a large number of characteristics, Areas of this type are well adapted for use in a wide variety of studies in which State data are neither sufficiently refined nor homogeneous and In which the manipulation of county data presents real difficulty. Moreover, a standard set of areas, such as these, makes possible studies in widely different fields on a comparable area basis.

These areas represent combinations of State economic areas. The 509 State economic areas are consolidated into a set of 121 areas which cut across State lines but which, as intended, preserve to a great extent the homogeneous character of the State economic areas. No changes were made in the boundaries of the 119 economic subregions of 1950 in conterminous United States. Two new subregions were established for the 1960 Census, one in Alaska and one in Hawaii. The economic subregions are perhaps best adapted to those analyses of the geographic distribution of characteristics of the population within the country as a whole in which there is no need for the recognition of State boundaries and in which the greater refinement permitted by the larger number of areas is desirable.

Figures on the population of the economic subregions and State economic areas by urban and rural residence are presented in table 38, and figure 7 shows the boundaries of the economic subregions and State economic areas. The State economic area in which a county is located is shown in table 24 in parentheses following the county name. A letter designates a metropolitan, and a figure a nonmetropolitan, State economic area.

Census tracts are small areas into which large cities and metropolitan areas have been divided for statistical purposes. Tract boundaries were established cooperatively by a local committee and the Bureau of the Census, and were generally designed to achieve some uniformity of population characteristics, economic status, and living conditions. Initially, the average tract had about 4,000 residents. Tract boundaries were established with the intention of being maintained over a long time so that comparisons may be made from census to census.

In 1960, population and housing data are published for tracts in 180 areas in the United States and the Commonwealth of Puerto Rico, and these areas contain more than 23,000 tracts (table 41). Tract data were tabulated for 8 cities in 1910 and 1920, 18 cities in 1930, and 60 areas in 1940. In 1950, reports were published for 64 tracted areas. As the foregoing suggests, tracts were initially established for cities as such; but, as the program expanded, tracts were extended to cover heavily settled areas adjacent to cities. In the decade 1950 to 1960, the Bureau made an effort to encourage local committees in this extension, with the ultimate objective of having tracts established in all standard metropolitan statistical areas. In 1960, all but 2 of the 180 areas were standard metropolitan statistical areas, and 136 such areas were completely tracted.

Statistics on the population and housing characteristics for each tracted area are published in Series PHC(1) reports, Census Tracts.