Montana
East of the divide the Missouri River, which is formed by the confluence of the Jefferson, Madison and Gallatin rivers near Three Forks, flows due north through the west-central part of the state to Great Falls. From this point, it then flows generally east through fairly flat agricultural land and the Missouri Breaks to Fort Peck reservoir. The stretch of river between Fort Benton and the Fred Robinson Bridge at the western boundary of Fort Peck Reservoir was designated a National Wild and Scenic River in 1976. The Missouri enters North Dakota near Fort Union, having drained more than half the land area of Montana (82,000 square miles (210,000 km2)). Nearly one-third of the Missouri River in Montana lies behind 10 dams: Toston, Canyon Ferry, Hauser, Holter, Black Eagle, Rainbow, Cochrane, Ryan, Morony, and Fort Peck.
What rivers form the Missouri River?
Jefferson, Madison and Gallatin rivers
East of the divide the Missouri River, which is formed by the confluence of the Jefferson, Madison and Gallatin rivers near Three Forks, flows due north through the west-central part of the state to Great Falls.
the Missouri River