The Red River Trails were a network of ox cart routes connecting the Red River Colony (the "Selkirk Settlement") and Fort Garry in British North America with the head of navigation on the Mississippi River in the United States. These trade routes ran from the location of present-day Winnipeg in the Canadian province of Manitoba across the Canada–United States border, and thence by a variety of routes through what is now the eastern part of the Dakotas and across western and central Minnesota to Mendota and Saint Paul, Minnesota on the Mississippi.

Travellers began to use the trails by the 1820s, with the heaviest use from the 1840s to the early 1870s, when they were superseded by railways. Until then, these cartways provided the most efficient means of transportation between the isolated Red River Colony and the outside world. They gave the Selkirk colonists and their neighbours, the Métis people, an outlet for their furs and a source of supplies other than the Hudson's Bay Company, which was unable to enforce its monopoly in the face of the competition that used the trails.

Free traders, independent of the Hudson's Bay Company and outside its jurisdiction, developed extensive commerce with the United States, making Saint Paul the principal entrepôt and link to the outside world for the Selkirk Settlement. The trade, developed by and along the trails connecting Fort Garry with Saint Paul, stimulated commerce, contributed to the settlement of Minnesota and North Dakota in the United States, and accelerated the settlement of Canada to the west of the rugged barrier known as the Canadian Shield. For a time, this cross-border trade even threatened Canada's control of its western territories. The threat diminished after completion of transcontinental trade routes both north and south of the border, and the transportation corridor through which the trails once ran declined in importance. That corridor has now seen a resurgence of traffic, carried by more modern means of transport than the crude ox carts that once travelled the Red River Trails.

In 1812, Thomas Douglas, 5th Earl of Selkirk, started a colony of settlers in British North America where the Assiniboine River joins the Red River at the site of modern Winnipeg. Although fur posts were scattered throughout the Canadian northwest, and settlements of Métis fur traders and bison hunters were located in the vicinity of Selkirk's establishment, this colony was the only agricultural settlement between Upper Canada and the Pacific Ocean. Isolated by geology behind the rugged Canadian Shield and many hundreds of miles of wilderness, settlers and their Métis neighbours had access to outside markets and sources of supply only by two laborious water routes.

The first, maintained by the Hudson's Bay Company (in which Lord Selkirk was a principal investor), was a sea route from Great Britain to York Factory on Hudson Bay, then up a chain of rivers and lakes to the colony, 780 miles (1,260 km) from salt water to the Assiniboine. The alternative was the historic route of the rival North West Company's voyageurs from Montreal through Lake Huron to Fort William on Lake Superior. Above Superior, this route followed rivers and lakes to Lac la Croix and west along the international border through Lake of the Woods to Rat Portage, and then down the Winnipeg River to the Red. The distance from the Selkirk settlement to Lake Superior at Fort William was about 500 miles (800 km), but Lake Superior was only the start of a lengthy journey to Montreal where furs and supplies would be transshipped to and from Europe.

Neither of these routes was suitable for heavy freight. Lighter cargoes were carried in York boats to Hudson Bay or in canoes on the border route. Both routes required navigation of large and hazardous lakes, shallow and rapid-strewn rivers, and swampy creeks and bogs, connected by numerous portages where both cargo and watercraft had to be carried on men's backs.

But geology also provided an alternate route, albeit across foreign territory. The valleys of the Red and Minnesota Rivers lay in the beds of Glacial Lake Agassiz and its prehistoric outlet Glacial River Warren; the lands exposed when these bodies of water receded were flat plains between low uplands covered by prairie grasslands. At the Traverse Gap, only a mile (1.6 km) of land separated the Bois des Sioux River, a source stream of the Red (which flowed north to Hudson Bay) and the Little Minnesota River, a source stream of the Minnesota River (tributary to the Mississippi, which flowed south to the Gulf of Mexico). The valley floors and uplands of the watercourses along this gently graded route provided a natural thoroughfare to the south. The eyes of the colonists therefore turned to the new United States, both as a source of supplies and an (illegal) outlet for their furs.

The rich fur areas along the upper Mississippi, Minnesota, Des Moines, and Missouri Rivers, occupied by Indigenous peoples, were exploited by independent fur traders operating from Prairie du Chien, Wisconsin in the late eighteenth century. At the beginning of the nineteenth century, these traders established fur posts in the Minnesota River valley at Lake Traverse, Big Stone Lake, Lac qui Parle, and Traverse des Sioux. The large fur companies also built posts, including the North West Company's stations at Pembina and St. Joseph in the valley of the Red River. The paths between these posts became parts of the first of the Red River Trails.