Most tribes require a specific percentage of Native “blood,” called blood quantum, in addition to being able to document which tribal member you descend from. Some tribes require as much as 25% Native heritage, and most require at least 1/16th Native heritage, which is one great-great grandparent.
Hereof, how many Native Americans are living on reservations?
About 22% of our country's 5.2 million Native Americans live on tribal lands (2010 U.S. Census). Living conditions on the reservations have been cited as "comparable to Third World," (May 5 2004, Gallup Independent).
Is an Indian reservation part of the United States?
A federal Indian reservation is an area of land reserved for a tribe or tribes under treaty or other agreement with the United States, executive order, or federal statute or administrative action as permanent tribal homelands, and where the federal government holds title to the land in trust on behalf of the tribe.