Assiniboine and Gros Ventre Tribes and Fort Belknap Reservation Timeline


Last Updated: 11 years

The largest and oldest histories of Montana Tribes are still very much oral
histories and remain in the collective memories of individuals. Some of that history has been lost, but much remains vibrant within community stories and narratives that have yet to be documented. This is a brief timeline of the Assiniboine and Gros Ventre tribes and the Fort Belknap Reservation.

Time Immemorial Creation –Iktomi and Earthmaker (The Keeper of the Flat Pipe) instructed the animals to dive for mud. Several animals were successful and the mud was used to make land on top of the water.

Traditional Life – The Assiniboine were part of the Yanktonai Sioux, living in the Lake Superior area. The Gros Ventre were linguistically affiliated with the Arapaho. Before their arrival in Montana, they were known to occupy lands in southern Saskatchewan and north to the Saskatchewan River.

1600 –The Assiniboine split off from the Sioux, and moved west toward the Lake of the Woods and Lake Winnipeg. Some Assiniboine bands moved farther west to the southern part of Saskatchewan.

1754 –The Gros Ventre had their first documented contact with whites between the north and south forks of the Saskatchewan River.

1780 – 1783 –Smallpox epidemics severely reduced the Gros Ventre population.

1793 –The Gros Ventre attacked the Hudson Bay Trading post, South Branch House. Most of the employees were killed.

Buy Assiniboine T-shirt1794 –The Gros Ventre attacked another Hudson Bay Trading Post, the Manchester House. The Gros Ventre suffered attacks from the Cree and Assiniboine who were being armed by the Hudson Bay trading posts.

1826 –The Gros Ventre met German explorer and naturalist Prince Maximilian, near the Missouri River in Montana. Artist Karl Bodmer accompanied Maximilian and they both painted portraits and recorded their meeting with the Gros Ventre.

1830 – 1832 –The Gros Ventre and Arapaho separated after a disagreement and killing on both sides. While the incident was resolved and peace restored, the groups held to the decision to separate.

1832 –The Gros Ventre engaged in a battle with trappers and Indians at Pierre’s Hole in Wyoming.

1843 –Assiniboine and Cree at the Sweet Grass Hills killed four hundred Gros Ventre.

1837 –1838 –Smallpox epidemic devastated the Assiniboine.

1851 –The Fort Laramie Treaty included the Assiniboine and Gros Ventre Cheyenne, Arapaho, Ogallala, Brule Sioux, Crow, Shoshone, Assiniboines, Gros Ventre, Mandans, Arikaras and Minnitarees – 10,000 Indians were in attendance. Article 5 described territories of the Gros Ventre and Assiniboine.


1853 –Treaty negotiations with the Gros Ventre at the Milk River. The Milk River country was the primary location of the Gros Ventre at this time. The following year, the tribe received one thousand dollars of food and annuities, along with the Piegan.


1855 –Judith River Treaty / Lame Bull Treaty – Common hunting grounds were determined and the Assiniboine had hunting privileges in common with the Blackfeet.


1866 –A raiding party of Pend d’Oreille stole horses from the Gros Ventre. The Gros Ventre tracked the horses to a camp of Piegans. Not knowing that the Piegans were not the raiders, the Gros Ventre retaliated, killing three people. This incident fueled continuing conflicts between the two tribes until the late 1870s.


1867–Fort Belknap was established on the south side of the Milk River. It served as both a fort and a trading post, and became the agency for the Gros Ventre and Assiniboine Indians in the area. The Fort was named after the Secretary of War at that time, William W. Belknap.


1873 and 1874 –President Grant issued Executive Orders. The 1873 Executive Order established and undivided territory for the Blackfeet, Gros Ventre, Assiniboine, and Sioux. The territory spanned lands north of the Missouri And Sun River. The 1874 Executive Order moved the southern boundary from the Sun River north to the Marias River.


1875 –President Grant issued an Executive Order restoring some of the lands diminished by his prior orders.


1880 –President Rutherford Hays took back the land that Grant had restored. This area included land around the Musselshell and Missouri River.


1884 –Gold was discovered in the Little Rockies on the reservation. Miners stake claims even though the gold is on Indian land.


1887–St. Paul’s Mission was established at the foot of the Little Rockies near Hays.


1888 –The Sweetgrass Hills Agreement established the Blackfeet, Fort Belknap and the Fort Peck Reservations.


1888 –Completion of the Great Northern Railroad, crossing reservation lands.


1895–The Tribes were pressured to sell land in the Little Rockies where gold was discovered. A piece of land seven miles long by seven miles wide was sold. Payment was $360,000. George Bird Grinnell led the commission negotiating this deal. This agreement ratified in 1896 is sometimes referred to as the Grinnell Treaty.


1908 –Winters V. United States: This US Supreme Court case was pivotal in determining reserved water rights for tribes. The Fort Belknap Tribes pursued the case as non-Indian settlers began diverting and using water from the Milk River on their northern border.


1909 –The Gros Ventre engaged a group of Crow and Lakota warriors south of the reservation. The site was named after Gros Ventre warrior, Red Whip, who killed twelve Lakota in the battle.

1924 –The Washington DC Bureau of Indian Affairs Office approved the Fort Belknap allotment plan. The government allotted 539,065 acres of land to 1,171 Indians enrolled at Fort Belknap. Tribal members received 40 acres of irrigable land and 320 acres of non-irrigable land. Lands not allotted on the Fort Belknap Reservation were not opened up to homesteading

1933 –As part of the New Deal program, the proposal to build Fort Peck Dam was authorized, resulting in tons of rock being hauled from Fort Belknap’s Snake Butte to the dam site. Original payment to be provided was 5 cents a ton. The tribes were able to negotiate for twenty-five cents a ton.

1934 –A delegation of tribal members traveled to Rapid City, South Dakota for the regional Indian Congress.

1935 –The Fort Belknap Tribes organized under the Indian Reorganization Act and adopt a Constitution and By-Laws.

1937–The tribes ratified a corporate charter August 25.

1941 – 1945 –Years of World War II, during which 25,000 American Indians served in the military, including Fort Belknap tribal members.

1974 –The Fort Belknap Tribal Constitution was amended to elect a council consisting of 12 representatives – six Gros Ventre and six Assiniboine.

1977 –The Zortman and Landusky mines began operation on the land that the tribes had been pressured to sell in 1895. The mines extracted gold from low-grade ore by cyanide heap-leach process.

1984 –Fort Belknap Community College was chartered.

1992 –Indian law Resource Center represented the Fort Belknap Tribes in case to shut the Zortman and Landusky mines down, citing degradation of the reservation’s water and air quality.

1994 –The tribal constitution was amended. The Fort Belknap Community Council make up was changed to four representatives from three districts (two districts get one representative and one district gets two). These representatives serve two-year terms. The chair and vice-chair run for election as a team and must include one Assiniboine and one Gros Ventre. These positions are four-year terms. The council then appoints a secretary/treasurer.

1998 –Pegasus Gold Inc., operators of the Zortman and Landusky mines, declared bankruptcy. Over 30 million dollars were spent on reclamation of the Zortman and Landusky open pit mines. The money fell short and the Bureau of Land Management spent around another 12 million to reclaim the area. Cyanide mining was banned in Montana.

2002 –Tribal enrollment changed, with tribal blood quantum lowered from one-fourth degree to one-eighth degree.