Respondents who identified themselves as American Indian were asked to report their enrolled or principal tribe. Therefore, tribal data in tabulations reflect the written entries reported on the questionnaires. Some of the entries (for example, Iroquois, Sioux, Colorado River, and Flathead) represent nations or reservations. The information on tribe is based on self identification and therefore does not reflect any designation of federally or state-recognized tribe. Information on American Indian tribes is presented in summary files. The information for Census 2000 is derived from the American Indian Tribal Classification List for the 1990 census that was updated based on a December 1997 Federal Register Notice, entitled "Indian Entities Recognized and Eligible to Receive Service From the United States Bureau of Indian Affairs," Department of the Interior, Bureau of Indian Affairs, issued by the Office of Management and Budget.