Established in 1879, Fort Assiniboine was one of the most strategically-placed U.S. Army posts in the northwest. Headquarters for the District of Montana, the fort and military reserve encompassed the entire Bears Paw mountain range. The 18th U.S. Infantry under the command of Colonel Thomas Ruger constructed the post with brick manufactured nearby. When completed, the fort's substantial brick buildings included officer's quarters, barracks, a large hospital, chapel, gymnasium, officer's club, stables, and warehouses. The U.S. Army intended the fort to protect settlers to the south from possible raids by Sitting Bull's Hunkpapa Sioux, who fled to Canada after Custer's defeat on the Little Big Horn in 1876. The military's fears proved groundless, however, as no serious Indian disturbance occurred in the area.
General John J. Pershing served here in the 1890s, earning his nickname "Black Jack" because of his association with the Afro-American 10th Cavalry - the famed "Buffalo Soldiers." For many years, Fort Assiniboine soldiers worked with the Canadian Mounties to control smuggling across the border.
The War Department abandoned the post in 1911. A few years later, the landless Chippewa and Cree Indians found a home on the southern part of the military reserve when it was set aside as Rocky Boy's Reservation. The State of Montana
purchased the fort's remaining buildings and 2,000 acres for use as the Northern Agricultural Research Center of Montana State University - Bozeman.