The Fort Belknap Indian Reservation is a semi-autonomous Native American-governed territory covering 1,014.064 sq mi (2,626.415 km²), and is located in north central Montana. This includes the main portion of their homeland, as well as off-reservation trust land. It is shared by two Native American tribes, the A'aninin (Gros Ventre) and the Nakota (Assiniboine). Its largest city is Fort Belknap Agency, at the reservation's north end.