Missouri River

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 before entering the Mississippi River north of St. Louis, Missouri. The river drains a sparsely populated, semi-arid watershed of more than 500,000 square miles , which includes parts of ten U.S. states and two Canadian provinces. Although nominally considered a tributary of the Mississippi, the Missouri River above the confluence is much longer and carries a comparable volume of water. When combined with the lower Mississippi River, it forms the world's fourth longest river system.
For over 12,000 years, people have depended on the Missouri River and its tributaries as a source of sustenance and transportation. More than ten major groups of Native Americans populated the watershed, most leading a nomadic lifestyle and dependent on enormous bison herds that roamed through the Great Plains. The first Europeans encountered the river in the late seventeenth century, and the region passed through Spanish and French hands before becoming part of the United States through the Louisiana Purchase.

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