A person's self-identified origin, descent, lineage, nationality group, or country in which the person or the person's parents or ancestors were born before their arrival in the United States. This item was asked on a sample basis.

This question was asked of persons regardless of how many generations their ancestors had been in this country. Persons were asked to write in the name of the group with which they most closely identify. Those who thought of themselves as having more than one origin were asked to write in their multiple ancestry, e.g., German-Irish. Instructions specified that religious groups were not to be reported as ancestry groups.

The open-ended write-in item on axes try was coded in census processing offices into a numeric representation using a code list containing over 400 categories. If a response was in terms of a dual ancestry, e.g., Irish-English, the person was assigned two codes, in this case one for Irish and one for English. Census basic record and public-use microdata files represent over 400 x 400 possible combinations. Selected three-ancestry combinations expected to be frequently reported were also coded, but, otherwise, whenever three or more ancestries are entered in a single response, only the first two were coded. Persons indicating two or more ancestries are shown in tabulations under "multiple ancestry" and may be counted more than once in tabulations of selected multiple-ancestry groups.

Most tabulations presenting counts of persons by ancestry show (a) the following single-ancestry groups: Dutch, English, French, German,
Greek, Hungarian, Irish, Italian, Norwegian. Polish, Portuguese,
Russian, (selected categories), Scottish, Swedish, Ukrainian, and other; (b) the number of persons reporting multiple ancestry, and the following selected multiple-ancestry groups: English and other group(s), French and other group(s), German and other group(s), Irish and other group(s), Italian and other group(s), and Polish and other group(s); and (c) ancestry not specified. Ancestry not specified includes nonresponses, also shown separately, as well as responses indicating religious groups, and unclassifiable responses. Only STF 4 presents more categories of ancestry than this at the State level or below.

Tabulations in STF 4 which present characteristics of specific ancestry groups at the State level or below present data for six single-ancestry groups--English, French, German, Irish, Italian, and Polish--and for four additional groups which vary from State to State. These four variable groups are the largest single- and/or multiple-ancestry groups in that State exclusive of (a) the six groups cited above, (b) all groups listed separately in the race and Spanish-origin questions, and (c) the category "American."