Name one of the two longest rivers in the United States.

The Missouri River is recognized as one of the two longest rivers in the United States. It flows approximately 2,341 miles, originating in the Rocky Mountains of Montana and emptying into the Mississippi River in St. Louis, Missouri. This extensive length makes it the longest river in the U.S.

The other river often considered in this context is the Mississippi River, which is approximately 2,340 miles long. Understanding the significance of these river systems is crucial for various reasons, including their impact on transportation, agriculture, and as a natural resource in the regions they traverse. Rivers like the Missouri also have historical importance, having been a key part of the exploration and settlement of the western United States.