Where does the missouri river begin?

Missouri River, longest tributary of the Mississippi River and second longest river in North America. It is formed by the confluence of the Jefferson, Madison, and Gallatin rivers in the Rocky Mountains area of southwestern Montana (Gallatin county), U.S., about 4,000 feet (1,200 metres) above sea level. read more

The Missouri River is the longest river in North America. Rising in the Rocky Mountains of western Montana, the Missouri flows east and south for 2,341 miles (3,767 km) before entering the Mississippi River north of St. Louis, Missouri. read more

The Missouri River's waters come from where the Jefferson, Madison and Gallatin Rivers converge. The river was very prone to flooding when the area first began to be settled by European settlers. These floods were a key part of the ecosystem in the area. read more