With coastal mountains and interior plains, the Americas have several large river basins that drain the continents. The largest river basin in North America is that of the Mississippi, covering the second largest watershed on the planet. The Mississippi-Missouri river system drains most of 31 states of the U.S., most of the Great Plains, and large areas between the Rocky and Appalachian mountains. This river is the fourth longest in the world and tenth most powerful in the world.