Sun River

The Sun River (also called the Medicine River) is a tributary of the Missouri River in the Great Plains, approximately 130 mi (209 km) long, in Montana in the United States.

It rises in the Rocky Mountains in two forks, the North Fork and South Fork, which join in the Flathead National Forest above Gibson Reservoir along the county line between Teton and Lewis and Clark counties. It flows E, SE, and E away from the mountains, past Simms, Sun River, and Vaughn and joins the Missouri at Great Falls.