The Gulf Coastal Plain extends from the Florida Parishes of Louisiana over most of Mississippi, some of western Tennessee and Kentucky, the southwestern 2/3 of Alabama, and the western panhandle of Florida. Its southern boundary is the Gulf of Mexico and its western boundary the drop into the Mississippi embayment. On the north it extends to the highlands of the Interior Low Plateaus and southern Appalachians. To the east, there is an arbitrary break with the South Atlantic Coastal Plain at the Alabama-Georgia border south through Florida along the Apalachicola River. The flat to rolling topography is broken by numerous streams and river bottoms. Uplands are dominated by pine, originally longleaf and slash in the south and shortleaf mixed with hardwoods in the north. These are fire-maintained systems that give way to loblolly pine and hardwoods in damper areas and bottomland hardwood forest in extensive lowland drainages.

Text taken from the public domain United States Bureau of Land Management website.