Where is the Missouri River?

The Missouri River is longer than the Mississippi, into which it flows after crossing much of the Great Plains. Unfortunately, it is not as navigable for much of its length.

Its tributaries begin in northern Wyoming and southern Montana. The Missouri itself touches 7 states, beginning near Three Forks in Montana, bisecting North and South Dakota, and forming the boundary between Nebraska and Iowa, and between Kansas and Missouri. It crosses Missouri west to east and joins the Mississippi River north of St Louis, on the west bank opposite Hartford, Illinois.