What is one of the two longest rivers in the United States?

The Nile River, although one of the longest rivers in the world, is not located in the United States, making it an incorrect choice for this question. The two longest rivers in the United States are the Missouri River and the Mississippi River. The Missouri River, in particular, is recognized as the longest river in the U.S. and runs through several states, starting in Montana and flowing into the Mississippi River at St. Louis, Missouri.

This makes the Missouri River the correct choice when identifying one of the two longest rivers in the United States. It plays a significant role in the geography, history, and economy of the regions it traverses, and understanding its importance can help in various citizenship-related discussions about U.S. geography and resources.