The National Park Service says the Missouri River is nearly 2,341 miles long, from Three Forks, Montana to its meeting with the Mississippi near St. Louis. Read on October 30, 2026.
By the It’s Missouri Editorial Team. Last reviewed October 30, 2026.
Where It Starts and Ends
- The river begins where the Gallatin, Madison and Jefferson Rivers meet at Three Forks, Montana, and joins the Mississippi River near St. Louis.
- Length depends on where you start counting; we read only the National Park Service page.
On the River in Missouri
See Missouri trails for the Katy Trail along it and the Lewis and Clark story.
More Missouri Guides
Sources
Checked October 30, 2026 by It’s Missouri. Cite this page: It’s Missouri (https://itsmissouri.com/answers/how-long-is-the-missouri-river/), checked October 30, 2026. Free to quote with a link.