Pocosins are naturally occurring freshwater evergreen shrub bogs or wetlands of the southeastern coastal plains. In 1962 pocosins still covered nearly 2.25 million acres in North Carolina-accounting for almost three-quarters of the pocosin ecosystems in the United States-but by 1979 forestry and farming operations had totally or partially altered all but about 700,000 of these acres. In 1985 the Environmental Protection Agency described North Carolina's pocosins as one of the most critically endangered of the nation's many wetland types.
The word "pocosin" is Algonquian in origin and is variously spelled "poquosin," "pequessen," "poccoson," and "percoarson." The generally accepted meaning of the word is "swamp on a hill." John Lawson made a number of references to pocosins in his book, A New Voyage to Carolina (1709), but ecologists, differentiating these often impenetrable formations from river bottomlands, wooded swamps, and marshes, have labored well into the twentieth century to arrive at a good, general definition. Pocosins have been described as "occurring in broad, shallow basins, in drainage basin heads, and on broad, flat uplands" and having "soils of sandy humus, muck or peat."
Some of the state's better-known pocosin areas include many of the Carolina Bays; the Green Swamp; Holly Shelter Swamp and Angola Bay; the Croatan National Forest; the Open Ground in Carteret County; the Alligator River National Wildlife Refuge; and, as of 1990, the Pocosin Lakes National Wildlife Refuge in Tyrrell and Washington Counties, said to feature some of the best remaining large pocosins in eastern North Carolina.