The Red River Colony, also known as Assiniboia, was a colonization project set up in 1811 by Thomas Douglas, 5th Earl of Selkirk, on 300,000 square kilometres (120,000 sq mi) of land in British North America. This land was granted to Douglas by the Hudson's Bay Company in the Selkirk Concession. It included portions of Rupert's Land, or the watershed of Hudson Bay, bounded on the north by the line of 52° N latitude roughly from the Assiniboine River east to Lake Winnipegosis. It then formed a line of 52° 30′ N latitude from Lake Winnipegosis to Lake Winnipeg, and by the Winnipeg River, Lake of the Woods and Rainy River.

The Selkirk Concession was a land grant issued by the Hudson's Bay Company (HBC) to Thomas Douglas, 5th Earl of Selkirk, in 1812. The Hudson's Bay Company held a commercial monopoly in Rupert's Land, consisting of the entire Hudson Bay drainage basin. The Selkirk Concession, also known as Selkirk's Grant, included a large section of the southwest area of Rupert's Land, bounded: on the north by the line of 52° N latitude roughly from the Assiniboine River east to Lake Winnipegosis, then by the line of 52° 30′ N latitude from Lake Winnipegosis to Lake Winnipeg; on the east by the Winnipeg River, Lake of the Woods and Rainy River; on the west roughly by the current boundary between modern Saskatchewan and Manitoba; and on the south by the rise of land marking the extent of the Hudson Bay watershed. This covered portions of present-day southern Manitoba, northern Minnesota and eastern North Dakota, in addition to small parts of eastern Saskatchewan, northwestern Ontario and northeastern South Dakota.