The Atchafalaya is different among Louisiana basins because it has a growing delta system ("see illustration") with wetlands that are almost stable. The basin contains about 70% forest habitat and about 30% marsh and open water. It contains the largest contiguous block of forested wetlands remaining (about 35%) in the lower Mississippi River valley and the largest block of floodplain forest in the United States. Best known for its iconic cypress-tupelo swamps, at , this block of forest represents the largest remaining contiguous tract of coastal cypress in the United States.