The reservation was established by congressional statute on September 7, 1916 (39 Stat. 739, Sec. 10), to provide land for the Rocky Boy's Band of Chippewa Indians, who had been forced out of territory in Minnesota and were landless. The Rocky Boy's Indian Reservation is located in the Bears Paw Mountains in north central Montana. According to the map of Montana, the reservation takes in land within the boundaries of Hill and Chouteau counties, about south of the Canada–United States border. It is the smallest reservation in the state in terms of land area, with a total land area of , which includes extensive off-reservation trust lands. The population was 3,323 at the 2010 census, an increase of 24 percent compared to 2000. Three other reservations of the seven in the state also had population growth during this period.