States the Missouri River Flows Through

America's Longest River

The Missouri River winds 2,341 miles from its Rocky Mountain headwaters to its confluence with the Mississippi River at St. Louis. Along the way, it traverses seven states:

1. Montana
2. North Dakota
3. South Dakota
4. Nebraska
5. Kansas
6. Missouri

Note on Iowa

While the Missouri forms part of Iowa's western border, the main channel does not flow through Iowa—it defines the boundary. The six states listed above contain the river's primary course.

Historical Significance

The Missouri served as the primary highway for Lewis and Clark's Corps of Discovery, steamboat commerce, and westward expansion, shaping the settlement pattern of the Great Plains.