The valley was long an area of habitation by various indigenous cultures, including the historic Ojibwe and Métis peoples. The river flows north through a wide ancient lake plain to Lake Winnipeg. The geography and seasonal conditions can produce devastating floods, with several recorded since the mid-20th century.

The western edge of the Red River Valley is a long ridge of land running north and south. This ridge is so small it is difficult to see in the southern part of the state. In the north, however, the ridge becomes the Pembina Mountains, a heavily wooded area near Walhalla, North Dakota.