Tribal census tracts are small, relatively permanent statistical subdivisions of a federally recognized American Indian reservation and/or off-reservation trust land. The optimum size for a tribal census tract is 2,500 people; it must contain a minimum of 1,000 people. The difference between a tribal census tract and a nontribal census tract is in the hierarchical presentation of the data. A tribal census tract is part of the American Indian hierarchy; that is, the tribal census tract is within a federally recognized American Indian reservation and/or off-reservation trust land.