River · United States
Missouri River
The Missouri River is the longest river in the United States and begins high in the Rocky Mountains of Montana. It crosses the wide prairies and joins the Mississippi just north of St. Louis.
Picture credit: w:User:Malepheasant (CC BY-SA 2.5) · Christopher Michel (CC BY-SA 4.0) · Wikimedia Commons
Where is the Missouri River?
The river starts here: Rocky Mountains in Montana, USA.
It ends in the Mississippi north of St. Louis.
Countries on the river: the United States.
The story behind it
People once called the Missouri the Big Muddy, because it carries so much sand and clay that the water looks like milky coffee. It starts as clear mountain streams, then winds through canyons and over endless grassland where bison graze and prairie dogs whistle from their burrows. Huge dams hold back parts of the river and turn it into long lakes that store water for dry summers. Further down, the river passes Omaha and Kansas City, and barges push loads of grain along it. In spring the melting snow and heavy rain can make the Missouri rise fast, so towns build high earth walls to keep the flood out. Two hundred years ago explorers followed this river upstream to reach the mountains, guided by people who had lived along its banks for a very long time.
Questions children ask
How long is the Missouri River?
The Missouri River is 3 767 km long. That makes it the longest river in the United States. Its whole course lies inside the country, from the Rocky Mountains to the Mississippi.
Which country does the Missouri River flow through?
The Missouri flows only through the United States. On its way it touches many states, among them Montana, Nebraska and Missouri. It never crosses a border into another country.
Where does the Missouri River flow into?
The Missouri flows into the Mississippi a little north of St. Louis. At that meeting point the muddy water of the two rivers can be seen side by side for a while. Together they then continue towards the Gulf of Mexico.
Where these numbers come from
Every figure on this page was checked against public reference sources before publication. Where sources genuinely disagree, the text says so.
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