The Gros Ventre, also known as the Aaniiih, A'aninin, Haaninin, Atsina, and White Clay, are a historically Algonquian-speaking Native American tribe located in northcentral Montana. Today, the Gros Ventre people are enrolled in the Fort Belknap Indian Community of the Fort Belknap Reservation of Montana, a federally recognized tribe with 7,000 members, also including the Assiniboine people.

The Saskatchewan River is a major river in Canada. It stretches about 550 kilometres (340 mi) from where it is formed by the joining of the North Saskatchewan River and South Saskatchewan River just east of Prince Albert, Saskatchewan, to Lake Winnipeg. It flows roughly eastward across Saskatchewan and Manitoba to empty into Lake Winnipeg. Through its tributaries the North Saskatchewan and South Saskatchewan, its watershed encompasses much of the prairie regions of Canada, stretching westward to the Rocky Mountains in Alberta and north-western Montana in the United States.