<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 also the largest river in the United States, and is the fourth longest river in the world. It originates in Lake Itasca, Minnesota, and flows through seven states before emptying into the Gulf of Mexico near New Orleans, Louisiana.