<human>:  With regards to the Mississippi River, what is the longest river in the United States?
<bot>: The Mississippi River is the longest river in the United States, with a length of 2,341 miles. It is the largest river in the contiguous United States and the fourth longest in the world. The Mississippi River drains an area of nearly 70,000 square miles and drains a drainage basin of 3,482,000 square miles.