Which river is one of the two longest in the United States?

The Missouri River is indeed one of the two longest rivers in the United States, along with the Mississippi River. Stretching over 2,300 miles, the Missouri River flows from the Rocky Mountains in Montana to the Mississippi River near St. Louis, Missouri. It plays a significant role in the geography and history of the U.S., serving as an important waterway for transportation and trade in the early days of American settlement.

The other options presented do not align with the criteria of being one of the two longest rivers in the U.S. The Nile and Amazon rivers are significant but are located outside the United States and are considered among the longest rivers in the world. The Rio Grande, while an important river in the U.S., primarily serves as a border between the United States and Mexico and is not among the longest rivers within the country. Thus, the Missouri River stands out as the correct answer to the question regarding the two longest rivers in the United States.