Missouri River: North America's Longest River, Flowing Through Seven States

The Missouri River is the longest river in North America at ~3,766 km (2,341 mi).

Course

• Source: Southwest Montana (Red Rock River)
• Flows through/borders: Montana, North Dakota, South Dakota, Nebraska, Iowa, Kansas, Missouri
• Confluence: Joins Mississippi River near St. Louis, Missouri

Significance

• Major transportation corridor (historic and modern)
• Water supply for agriculture, municipalities, industry
• Habitat for diverse fish and wildlife
• Six mainstem dams (Pick-Sloan Plan) regulate flow

The Missouri is a defining feature of the Great Plains and the Mississippi watershed.