According to the United States Census Bureau, approximately 4.9 million people in the U.S., or 1.6%, identified as Native American in combination with another ethnic identity in 2008. There are currently around 335 federally recognized tribes in the United States (minus Alaska), most of which have reservations as national homelands. More than half of American Indians live off-reservation, many in large cities.

American Indian nations are theoretically sovereign but limited by individual treaties and federal Indian law, which is in flux and often dependent on individual U.S. Supreme Court decisions. The government has treaty and trust obligations toward indigenous nations, stemming from historical land sales by Indian nations to the federal government and the assumption of a continuing guardianship over them. Separate federal agencies, such as

the Bureau of Indian Affairs and the Indian Health Service, are responsible for the federal government’s responsibilities to Indian tribes.