Missouri River: Facts About the Longest River in North America

Here are some facts about the Missouri River.

  • The Missouri River is the longest river in North America, and it is 2,341 miles long. It flows from its source in the Rocky Mountains in Montana to the Mississippi River near St. Louis.

  • The Missouri was formed about 30 million years ago. However, the present course was formed about 115,000 years ago when streams from the Rocky Mountains were diverted by glaciers.
  • The Missouri River basin covers about 529,350 square miles, which is about 15 percent of North America. Almost 30 Native American Indian tribes live within the basin.
  • The Missouri River basin is home to a wide variety of animal and plant life. There are an estimated 300 species of birds and 150 species of fish.
  • About 87,000 cubic feet of water per second is discharged by the river. The Continental Divide forms most of the western edge of the river’s watershed.
  • In 1804, Lewis and Clark were the first Europeans to travel the entire length of the river. Many place names and geographic features take their names from their expedition.
  • The Missouri was largely responsible for expansion westwards in the United States. Steamboats were a popular means of transport along the river during the early 19th century.
  • One of the steamboats, the Arabia, was buried under 40 feet of mud and remained missing for over a century before being found half a mile from the present course of the river.

Missouri River

  • The Missouri National Recreation Area stretches for over 100 miles along the Nebraska / South Dakota border. The area offers boating, fishing and various water sports.
  • The river can be followed by walking along the Lewis and Clark historic trail, which follows the entire length of the river. There are about 100 historic sites along the trail.

What next? Learn more river facts by visiting our rivers resources page.