The 1980 census was the first census since 1910 to collect extensive data on American Indian tribes. This two-section report is based on the 1980 census sample (approximately 19% of housing units), and contains 27 extensive data tables describing demographic and economic characteristics of U.S. American Indian tribes. Tables estimate 1980 census population totals for each tribe for the nation, regions, divisions, states, and selected counties. All tribes, clans, bands, or groups with at least 30 persons are included. Characteristics presented at the national and state levels include age, sex, household and family type, fertility rate, language, educational attainment, school enrollment, labor force participation, occupation, income, and poverty status. Some information is offered for American Indians living on reservations, tribal trust lands (off reservations), and the historic areas of Oklahoma (excluding urbanized areas), and for American Indians, Eskimos, and Aleuts living in Alaska Native villages. Census data are based on self-identification and thus may differ from data of other sources, such as tribal governments or the Bureau of Indian Affairs. An introduction describes data sources and related materials and the organization of this report. Appendices explain: (1) area classifications; (2) subject characteristics and comparability of 1980 data with 1970 census data; (3) general enumeration and processing procedures; (4) sample design, estimation procedures, and data accuracy; and (5) the census publications and computer tape program. Facsimiles of respondent instructions and questionnaire pages are included. (SV)