From abstract: The Coastal Plain of South Carolina extends from the Atlantic Ocean inland a distance ranging from 120 to 150 miles to the Fall Line, where it adjoins the Piedmont province. It includes an area of more than 20,000 square miles, or nearly two-thirds of the State, whose total area is 30,981 square miles, of which 494 square miles is water. The geographic divisions of the Coastal Plain are the marine coastal terraces, or "low country", which stand less than 270 feet above sea level, and the Aiken Plateau, the High Hills of Santee, the Richland red hills, and the Congaree sand hills.