<P> 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 . The river takes drainage from a sparsely populated , semi-arid watershed of more than half a million square miles ( 1,300,000 km ) , which includes parts of ten U.S. states and two Canadian provinces . When combined with the lower Mississippi River , it forms the world 's fourth longest river system . </P>
<P> 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 . The river takes drainage from a sparsely populated , semi-arid watershed of more than half a million square miles ( 1,300,000 km ) , which includes parts of ten U.S. states and two Canadian provinces . When combined with the lower Mississippi River , it forms the world 's fourth longest river system . </P>
where does the missouri river and the mississippi river meet
where does the missouri river and the mississippi river meet
north of St. Louis , Missouri
north of St. Louis , Missouri