The Raccoon River is a 30.8-mile-long (49.6 km) tributary of the Des Moines River in central Iowa in the United States. As measured using the longest of its three forks, its length increases to 226 miles (364 km). Via the Des Moines River, it is part of the watershed of the Mississippi River. The river runs through an intensely cultivated area of croplands and livestock farming, receiving Tile drainage from slow-draining rich natural bottomland.