Which river is considered the longest in the United States?

The Missouri River is recognized as the longest river in the United States, stretching approximately 2,341 miles. It begins in the Rocky Mountains of Montana and flows into the Mississippi River, effectively contributing to a larger river system. Its journey encompasses several states and plays a critical role in the ecology, economy, and history of these regions, serving as a vital water source and transportation route.

The other rivers, while significant in their own right, do not match the Missouri River's length. The Mississippi River, often popularly known for its critical role in American history and culture, is approximately 2,340 miles long, making it slightly shorter than the Missouri. The Colorado River and the Rio Grande, while essential for both their environmental and cultural contributions, are not close to the lengths of the Missouri or Mississippi rivers, further emphasizing the unique stature of the Missouri River in terms of length.