The Atlantic Coastal Plain

The Atlantic Coastal Plain is the broad, flat lowland that fringes the eastern and southern edge of the country, widening from a thin strip in New Jersey and New York to hundreds of miles across the Carolinas, Georgia, and Florida, then wrapping around the Gulf of Mexico to Texas. It is the emerged seafloor of the continent - sandy, low, and gently sloping, never far above sea level.

Its inland edge is the fall line, where rivers tumble off the harder rock of the Piedmont and where colonial port cities grew. Toward the coast it dissolves into pine forests, swamps and marshes, sluggish blackwater rivers, and a long chain of barrier islands. Warm, wet, and vulnerable to hurricanes and rising seas, the coastal plain holds much of the country's fastest-growing coastal population.

• The Piedmont
  The rolling upland between mountains and coast related