The Okefenokee Swamp is a shallow, 438,000-acre (177,000 ha), peat-filled wetland straddling the Georgia–Florida line in the United States. A majority of the swamp is protected by the Okefenokee National Wildlife Refuge and the Okefenokee Wilderness. The Okefenokee Swamp is considered to be one of the Seven Natural Wonders of Georgia and is the largest "blackwater" swamp in North America.

A swamp is a forested wetland. Swamps are considered to be transition zones because both land and water play a role in creating this environment. Swamps vary in size and are located all around the world. The water of a swamp may be fresh water, brackish water, or seawater. Freshwater swamps form along large rivers or lakes where they are critically dependent upon rainwater and seasonal flooding to maintain natural water level fluctuations. Saltwater swamps are found along tropical and subtropical coastlines. Some swamps have hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodic inundation or soil saturation. The two main types of swamp are "true" or swamp forests and "transitional" or shrub swamps. In the boreal regions of Canada, the word swamp is colloquially used for what is more formally termed a bog, fen, or muskeg. Some of the world's largest swamps are found along major rivers such as the Amazon, the Mississippi, and the Congo.