An Indian reservation is land a tribe reserved for itself when it relinquished its other land areas to the U. S. through treaties. More recently, Congressional acts, Executive Orders and administrative acts have created reservations. There are approximately 275 Indian land areas in the U. S. administered as Indian reservations (reservations, pueblos, rancherias, communities, etc.). The largest is the Navajo Reservation of some 16 million acres of land in Arizona, New Mexico, and Utah. Many of the smaller reservations are less than 1,000 acres with the smallest less than 100 acres. On each reservation, the local governing authority is the tribal government.
The United States holds approximately 56.2 million acres of land in trust for various Indian tribes and individuals. Much of this is reservation land; however, not all reservation land is trust land. The states in which reservations are located have limited powers over them, and only as provided by Federal law. On some reservations, however, a high percentage of land is owned and occupied by non-Indians. Some 140 reservations have entirely tribally owned land.