Missouri River

Missouri River, also called the Big Muddy, is the longest river in North America. It rises in the Rocky Mountains of western Montana, a state in the United States, and flows eastwards and southwards for 2,341 miles (3,767 km) 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 (1,300,000 sq km), which includes parts of ten U.S. states and two Canadian provinces.