An Indian reservation is a legal designation for an area of land managed by a Native American tribe under the US Bureau of Indian Affairs, rather than the state governments of the United States in which they are physically located. Each of the 326 Indian reservations in the United States are associated with a particular Nation. Not all of the country's 567 recognized tribes have a reservation—some tribes have more than one reservation, some share reservations, while others have none. In addition, because of past land allotments, leading to some sales to non-Native Americans, some reservations are severely fragmented, with each piece of tribal, individual, and privately held land being a separate enclave. This jumble of private and public real estate creates significant administrative, political, and legal difficulties.