A swamp is a wetland with areas of open water that are usually relatively deep. A variety of trees and plants grow in a swamp, and swamps provide a habitat for thousands of species of wildlife. The U.S is home to more than a dozen swamps. Swamps usually contain fresh or brackish water, but high levels of salt in the water can kill many species of plants that grow in a swamp. Salt water intrusion is a major concern in Louisiana’s swamps.