The U.S. Census Bureau has two main programs designed to collect and maintain geographic information on tribal areas: the Boundary and Annexation Survey (BAS) and the Participant Statistical Areas Program (PSAP). Please see the links below for more information on these programs and American Indian and Alaska Native geography.

BAS provides tribal governments an opportunity to review the Census Bureau's legal boundary data to make sure the Census Bureau has the correct boundary, name, and status information. The Census Bureau uses the boundaries collected in BAS to tabulate data for various censuses and surveys including the decennial census and the American Community Survey.

In February 2014, the Census Bureau and the National American Indian Housing Council signed a Memorandum of Agreement in support of the Tribal BAS.

In April 2025, the Census Bureau and the Bureau of Indian Affairs signed a Memorandum of Agreement in support of the Tribal BAS.

In support of the government-to-government relationship with federally recognized American Indian tribes, the Census Bureau works directly with tribal officials to maintain a current and comprehensive inventory of legally defined tribal lands. Detailed information about current Tribal BAS participation, materials and webinars can be accessed at the BAS website.