The Atchafalaya River is a 137-mile-long (220 km)distributary of the Mississippi River and Red River in south central Louisiana in the United States. It flows south, just west of the Mississippi River. The Atchafalaya River is navigable and provides a significant industrial shipping channel for the state of Louisiana, as well as the cultural heart of the Cajun Country. The maintenance of the river as a navigable channel of the Mississippi River has been a significant project of the U.S. Army Corps of Engineers for over a century. The river valley forms the Atchafalaya Basin and Atchafalaya Swamp located in southern Louisiana near the Gulf of Mexico.