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The 10 Longest Rivers in Montana

The Missouri River is the longest river in the U.S. state of Montana.

The U.S. state of Montana has been nicknamed the "Mountain State." Located in the western part of the country, numerous major rivers flow through the state, including the Missouri River, Milk River, Yellowstone River, Kootenai River, and Bighorn River. Some of these rivers are highlighted below.

The Longest rivers in Montana

Missouri River

The Missouri River is the longest river and has a total length of 2,340 miles. The Missouri River originates from the Rocky Mountains in western Montana and flows eastward before entering the Mississippi River near St. Louis, Missouri. The river has been of great significance to the residents of Montana for the past 12,000 years, as it has been used as a means of transport and a mode of sustenance. The river's name originated from the Missouri tribe, whose name means “people with wooden canoes.” The Missouri River ranks as the 15th longest river in the world.

Milk River

The Milk River has an approximate length of 729 miles, making it the second longest river in Montana. The river passes through the United States and enters the Canadian province of Alberta. The water of the Milk River contains a peculiar whiteness that resembles the color of tea. This white color is the result of silt and clay suspended in the water.

Yellowstone River

The Yellowstone River has a length of 692 miles and ranks as the third longest river in Montana. It is a tributary of the Missouri River, its primary source is the confluence of the North and South and Forks. The river flows through the U.S. states of Montana, North Dakota and Wyoming. Native Americans initially used the Yellowstone River as a mode of transport and as a source of water for irrigation purposes.

Kootenai River

The Kootenai River has a length of 485 miles and ranks as the fourth longest river in Montana. The river passes through the Canadian province of British Colombia, Idaho, and Northern Montana. The Kootenai River is the largest river in North America that drains into the Pacific Ocean. Various dams have been built along the river to generate hydroelectric power. A larger portion of the Kootenai River lies in Canada (more than 70 percent), while Idaho and Montana contain 6 percent and 23 percent of the river, respectively.

Bighorn River

The Bighorn River is a stream of the Yellowstone River that has a length of 461 miles and flows through the U.S. states of Montana and Wyoming. It is the fifth longest river in Montana and has three sections: the Wind River located in Wyoming; the Lower Big Horn River located in Montana; and the Big Horn River located in both Wyoming and Montana.

Other Long Rivers in Montana

Montana is a large state and numerous rivers either pass through or originate from this state. Other significant rivers in Montana include the Powder River, Clark River, Musselshell River, Tongue River and Frenchman River. The Frenchman River is 212 miles long and is the tenth longest river in Montana.

The 10 Longest Rivers in Montana

RankRiverLength (miles)Length (km)
1Missouri River 2,3403,770
2Milk River7291,173
3Yellowstone River6921,114
4Kootenai River485781
5Bighorn River 461742
6Powder River 375604
7Clark Fork310500
8Musselshell River292470
9Tongue River265426
10Frenchman River 212341

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