A river basin is a large land area that is drained by a number of streams and rivers that come together and feed into a larger river. This river eventually flows into the ocean. The Atchafalaya Basin in St Martin Parish is the largest freshwater river basin in the world. Located in south central Louisiana, this basin contains 500,000 acres of swamps, lakes and bayous. It stretches from near Simmesport in the north through parts of eight parishes to the Morgan City southern area. It differs from other freshwater basins as it has a growing delta system with almost steady wetlands. It is known for its iconic cypress forests and swamps.