Red River Of The North, a stream rising in Elbow lake, 1,680 ft. above the sea, on the border of Becker and Beltrami counties, Minnesota, in about lat. 47° 10' N. and lon. 95° 25' W. It flows S. for about 100 m. through several small lakes to Otter Tail lake in the county of the same name, and thence W. 100 m. to Breckinridge, Wilkin co. (lat. 46° 15', lon. 96° 35'), whence it runs N. about 550 m., separating Dakota from Minnesota and dividing Manitoba into two unequal parts, and empties into the S. extremity of Lake Winnipeg (628 ft. above the sea) through six mouths, amid extensive marshes, about lat. 50° 30' and lon. 96° 50'. It is very tortuous, its length being about twice that of straight lines following its three principal directions. The portion between Breckinridge and Otter Tail lake is also called Otter Tail river, the term Red river being sometimes restricted to the portion below Breckinridge. It is sluggish, except at the rapids or chutes, flowing through a very flat prairie, between clay banks varying from 20 to 60 ft. in height. The area within the United States drained by it is about 32,000 sq. m., in which the annual rainfall is comparatively small. The water is muddy but agreeable to the taste.

The river is subject to annual spring freshets, very variable in duration and height, which are due to ice gorges. Its valley is but thinly settled. The principal towns along its banks, all of which are small, are Breckinridge, McCauleyville, and Moor-head in Minnesota, Fargo and Pembina in Dakota, and Winnipeg or Fort Garry in Manitoba. Between Moorhead and Fargo, 50 m. N. of Breckinridge, the Northern Pacific railroad crosses it. The business on the river consists principally in carrying supplies for the settlements in Manitoba and bringing back furs. Two or three small steamers ply in summer between Moorhead and Fort Garry, and a considerable amount of freight is floated down in flats. At Breckinridge the Red river receives the Bois de Sioux or Sioux Wood river, flowing N. from Lake Traverse. The chief tributaries from the west are the Wild Rice, Cheyenne, Elm, Goose, Turtle, Big Salt, Little Salt, and Pembina rivers in Dakota, and the Scratching and Assiniboin rivers in Manitoba, the latter being its largest affluent.

From the east the principal tributaries are the Buffalo, Sand Hill, Red Lake, Snake Hill, and Two rivers in Minnesota, and the Roseau or Redgrass river and the rivière Seine in Manitoba. These streams drain an immense number of small lakes.