Tribes also have varying eligibility criteria for tribal membership. Tribal Indians and tribes have a special relationship with the United States government that derives from their political status, not race or ethnicity. A community of Indians who are ethnologically similar, but also exist in a legal-political sense. An Indian tribe is often a body of people bound together by blood ties who are socially, politically, and religiously organized, may live together in a defined territory, and speak a common language. When two or three tribes were placed on one reservation, they were called confederated tribes, but they still constitute separate tribes generally.
Tribes can define their own membership criteria, among other powers.
There are 560 federally-recognized tribes in the United States, including 227 village groups in Alaska. Each tribe is unique in culture, history, and governmental structure. Federal recognition is now generally achieved by a statutorily defined Bureau of Indian Affairs administrative process. Some tribes have been recognized by states, even though they do not have federal recognition. For further clarification of these terms, please read the next section.