Wyoming has the least land area within the Mississippi River basin.

Only a small part of Wyoming drains into the Mississippi River basin, making it the state with the smallest land area. Although Wyoming is on the western boundary of the Mississippi River basin, which includes 31 states in the United States, a large portion of its water flow is diverted to other drainage basins. As a result, in comparison to other states, Wyoming's contribution to the Mississippi River basin is somewhat little.