Early region, western Canada.
Named for the Assiniboin Indians, it was an area with indefinite boundaries, controlled by the Hudson's Bay Co. с 1811–70. It included present-day southern Manitoba and until 1818, present-day North Dakota and Minnesota. It was incorporated into Manitoba in 1870. In 1882 the Canadian government created another district of Assininboia as part of the old Northwest Territories. In 1905 this district was divided between Alberta and Saskatchewan.