The Missouri River, one of the longest and most important rivers in North America, stretches approximately 4,087 kilometers from the Rocky Mountains in western Montana to its confluence with the Mississippi River near St. Louis, Missouri. As the most important tributary of the Mississippi, it flows through seven U.S. states—Montana, North Dakota, South Dakota, Nebraska, Iowa, Kansas, and Missouri—and, with its extensive drainage basin of approximately 1.3 million square kilometers, shapes the landscape, economy, and history of the Great Plains.

The river originates in the rugged, snow-capped peaks of the Rocky Mountains, more precisely at Hell Roaring Creek, and winds through vast prairie areas, deep canyons, and fertile plains. Its upper reaches are characterized by clear, wild currents, while in its middle reaches it meanders through the vast plains of the Great Plains. In its lower reaches, it becomes a calmer, navigable body of water, regulated by numerous dams. Among the most important dams are the Fort Peck Dam and the Oahe Dam, which not only control water flow but also contribute to power generation and irrigation.
Historically, the Missouri River was a vital lifeline for indigenous peoples, including the Sioux, Cheyenne, and Mandan, who used its banks for hunting, fishing, and trade. In the 19th century, it became the lifeline of the U.S. westward expansion, particularly through the Lewis and Clark Expedition (1804–1806), which used the river as a route to the unknown West. Steamboats later revitalized trade before railroads and modern infrastructure changed the river's role.
Today, the Missouri River is not only essential for agriculture and energy supply, but also a hotspot for recreational activities such as fishing, boating, and hiking. However, the Missouri River remains a symbol of the wild beauty and complex history of the United States.