Discover The Longest River In The US

Written by Jeremiah Wright
Published: May 27, 2022
Image Credit Jacob Boomsma/
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You might instantly be thinking of the Mississippi River when you’ve read this article’s title, but it is NOT the longest river existing in the US, even despite its fame. Some of you have debated it for a while, but the longest river record does not belong to the breathtaking “old man river,” just like the others say. 

Although the Mississippi has played a vital role in the industrialization of the United States and has been a source of hydroelectric energy and drinking water for millions of locals, there is something still more extensive than the said river, and we are about to find out soon enough.

For today’s topic, we will put an end to the never-ending question of others as to what is the longest river in the US and why it is not the Mississippi River.

What is the longest river in the US?

A tributary of the famous Mississippi River, the Missouri River is considered the longest river in the US, just west of Bozeman in Montana. This river is regarded as the “Center of Life” around the Great Plains, as it has served as the primary source of food, trade, transportation, and exploration for millions over the years. It had a considerable impact on the culture of America in the past, and it still does, even in the present and in the future. At least one-fourth of the agriculture in the US is found in the watershed of the Missouri River, which makes room to produce one-third of the country’s barley, oats, and wheat.

Lake Sharpe South Dakota
The Missouri River is considered the longest river in the US.

Harry Weddington, U.S. Army Corps of Engineers / This image or file is a work of a U.S. Army Corps of Engineers soldier or employee, taken or made as part of that person’s official duties. As a work of the U.S. federal government, the image is in the public domain.

How long is it compared to the Mississippi River?

The Missouri River stretches 2,466 miles, while the Mississippi River is 2,340 miles long, about a hundred miles apart from their respective lengths.

What area does the Missouri River flow through?

The Missouri River flows almost entirely through the United States, crossing seven states. Howieson

The Missouri River flows almost entirely through the United States, crossing seven states: Montana, North Dakota, South Dakota, Nebraska, Iowa, Kansas, and Missouri. The river starts where the Jefferson, Madison, and Gallatin rivers meet in Montana. It flows into its main tributary, the Mississippi River, just north of St. Louis in Missouri.

How much water does the Missouri River drain compared to the Mississippi River?

Even though the Missouri River is slightly longer than the Mississippi, it only drains 529,200 square miles, comprising parts of ten U.S. states and two Canadian provinces. However, the Mississippi River drains 1.2 million square miles, including parts of 32 states and two Canadian provinces, approximately 40% of the continental United States. When combined as tributaries, the two rivers carry more water than any American river.

Does the Missouri River have any unique qualities?

The Missouri River is considered one of the most changed rivers in the U.S. due to its dams and reservoirs. The dams and reservoirs created lakes that somehow stopped and controlled the river’s free-flowing nature, thus preventing flooding in many vulnerable areas.

The river basin of the Missouri River was also extensively developed for irrigation and flood control during the 20th century. During this time, hydroelectric power generation started and made life easier for locals around the area.

One of its most significant and unique features ever known was its capacity to hold a large amount of silt soil, which caused the river to be been given the nickname “Big Muddy.” Its name alone, Missouri, is derived from one of the Missouri tribes’ names, which means “people with wooden canoes.”

Over 95 virtual tributaries and hundreds of minor variants feed the Missouri River, including its chief tributaries, the Cheyenne, Niobrara, Platte, and Yellowstone rivers.

How many species of animals are there within the Missouri River?

White-tailed deer standing in the snow in the winter.
The Missouri River is home to 150 species of fish, 301 species of birds, 60 species of mammals, and 52 species of reptiles and amphibians.

Michael Sean OLeary/

The river is not just known for being the longest in the United States, but it is also known for holding such a great variety of wildlife. The Missouri River is home to 150 species of fish, including the prehistoric-looking paddlefish and the endangered pallid sturgeon, 301 species of birds, including the northern cardinal and blue jay, 60 species of mammals, such as the trophy elk and white-tail deer, and 52 species of reptiles and amphibians.

Animals that are commonly found within the Missouri River are:




Reptiles & Amphibians

What are other facts about the Missouri River?

Missouri National Recreational River
The Missouri National Recreation Area allows tourists and locals to fish, boat, and enjoy recreational water activities.

Jacob Boomsma/

  • For over 12,000 years, the Missouri River has served many different purposes to the locals living around it. The river and its tributaries have become a means of transportation, water source, irrigation, and fishing.
  • Many believe that the Missouri River formed around 30 million years ago. Yet, due to its changes in course as time passes by, the current period of the river is estimated to be 115,000 years old.
  • The river was accidentally spotted and discovered in 1673 when two French explorers named Louis Joliet and Father Jacques Marquette were floating along the Mississippi River.
  • In 1804, explorers Meriwether Lewis and William Clark, along with 40 other men in their crew, were the first to travel the entire length of the Missouri River.
  • An estimated population of 10 million people lives in the basin of the Missouri River. This number includes residents from 10 states, a small region in Canada, and 28 Native American tribes.
  • There is a 100-mile-long area designated along the South Dakota and Nebraska borders as the Missouri National Recreation Area, allowing tourists and locals to fish, boat, and enjoy recreational water activities.
  • Several national parks are located within the Missouri River watershed, including Glacier National Park, Badlands National Park, Rocky Mountain National Park, and Yellowstone National Park.
  • The Missouri River is the 15th longest river in the world.
  • The river has many nicknames, including “Big Muddy,” “Dark River,” “Wide Missouri,” “Father of Rivers,” and “Pekitanoui.”

Missouri National Recreational River
Missouri National Recreational River
Jacob Boomsma/
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About the Author

I hold seven years of professional experience in the content world, focusing on real estate, nature, and wildlife. Asides from writing, I enjoy surfing the internet and listening to music.

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