The Shonkin Sag is a prehistoric fluvioglacial landform located along the northern edge of the Highwood Mountains in the state of Montana in the United States. The Sag is a river channel formed by the Missouri River and glacial meltwater pouring from Glacial Lake Great Falls. It is one of the most famous prehistoric meltwater channels in the world.[1]
- ^ Axline, Jon and Bradshaw, Glenda Clay. Montana's Historical Highway Markers. Rev. ed. Helena, Mont.: Montana Historical Society, 2008, p. 91.