A swamp is a wetland that is permanently saturated with, or filled with, water and dominated by water-tolerant trees and other woody vegetation. Swamps exist exist throughout the world in areas that both have poor drainage and sufficient supplies of water to keep the ground waterlogged and whose water contains a sufficient concentration of minerals to promote the decay of organisms and prevent the accumulation of organic matter.
Swamp water can be fresh water, brackish water, or saltwater. Freshwater swamps are found mainly along large rivers or lakes, where they depend on rain and seasonal flooding to maintain their water levels, while saltwater swamps occur along tropical and subtropical coastlines.
Marshes differ from swamps in that they are dominated by grasses and other soft-stem vegetation instead of trees. Bogs differ from swamps in that they are typically found at higher altitudes and latitudes, their soil is spongy, peat-filled, and less nutrient-rich, and they have lesser variety of plant and animal species.