Major rivers in the United States included the Mississippi River, the Colorado River, the Missouri River, the Columbia River and the Rio Grande River. The longest river in the country is the Missouri River, which runs from headwaters in Montana to the Mississippi River in Missouri. The combined length of the Mississippi, Missouri and Jefferson rivers is 3,902 miles, which makes them the fourth-longest river in the world when seen as one continuous stream.
The Mississippi River is the largest river by volume and has the third-largest drainage system in the world. The Mississippi and its tributaries, such as the Missouri and Ohio Rivers, are important commercial routes, allowing large ships to reach large interior cities such as St. Louis, Pittsburgh and Minneapolis.
The Colorado River runs from Colorado to Mexico and provides water and hydroelectric power to much of the Southwest. The Columbia River runs through Washington State and Oregon, providing shipping routes to the farming regions in the interiors of those states, as well as hydroelectric power. The Rio Grande forms part of the border with Mexico and provides irrigation water to Texas and surrounding states.
Other major rivers include the Yukon River in Alaska and the St. Lawrence River, which forms the border with Canada in the Northeast United States and allows large ships to reach the Great Lakes.