The 10 Longest Rivers in Iowa

The US state of Iowa is located in the Midwestern region of the nation. The state is bordered by six states as well as four rivers. These rivers are the Mississippi River, which forms part of the border with Illinois and Wisconsin, while the Missouri River forms the border with Nebraska. The Big Sioux River is part of the border with South Dakota, while the Des Moines River forms about 20 miles of the boundary between Iowa and Missouri. Interestingly, all rivers in Iowa are part of the massive Mississippi River Watershed, which is made up of the Missouri River Drainage Basin and the Upper Mississippi River Drainage Basin.

The Longest Rivers in Iowa

The Missouri River is the longest in Iowa and runs for a length of about 2,340 miles. The Missouri River is followed closely by the Mississippi River, which with has an approximate length of 2,320 miles. The Des Moines River is in the third longest, but with a length of only 525 miles, it is significantly shorter the Missouri and Mississippi. The Big Sioux River and the Cedar River rank as the fourth and fifth longest, with lengths of 419 miles and 338 miles, respectively. The shortest on the list the 10 longest rivers is the Chariton River, which is 218 miles long.

Missouri River

The Missouri River is the longest in all of North America, and its course stretches from the Rocky Mountains until it drains into the Mississippi River. The river’s watershed is responsible for draining a region with an area of more 500,000 square miles, which includes part of 10 US states and 2 Canadian. Some of the largest tributaries of the Missouri River include runoff from the Yellowstone River and Platte River.

Mississippi River

Flowing entirely within the US (through ten US states), the Mississippi River is the major contributor of North America’s second-largest drainage structure. With its massive size, the river’s watershed is responsible for the drainage of 31 states and 2 Canadian provinces. The Mississippi River originates at Lake Itasca, and eventually drains into the Gulf of Mexico.

Des Moines River

The Des Moines River is the largest river that flows across the state. The Des Moines begins at southern Minnesota, and eventually drains into the Mississippi River. One sources of the river is Lake Shetek in Murray County, Minnesota, while the other branch rises from Okamanpeedan Lake in Emmet County. The two forks eventually join in Humboldt County. Some of its tributaries include the Boone River and the Raccoon River. For perspective, the length of the Des Moines River (525 miles) is at least four times smaller than the Missouri and Mississippi.

Chariton River

With a length of 218 miles, the Chariton River is the shortest on the list of the longest rivers in Iowa. The Chariton River begins in Clarke County, and eventually joins up with the Missouri River in Chariton County. Interestingly, all rivers and streams to its west flow into the Missouri River, while those to the east flow into the Mississippi. For this reason, the river has been dubbed Missouri's "Grand Divide."