Did You Know? South Carolina is bordered to the north by North Carolina; to the south and west by Georgia, located across the Savannah River; and to the east by the Atlantic Ocean. South Carolina is composed of four geographic areas, whose boundaries roughly parallel the northeast/southwest Atlantic coastline. The lowest part of the state is the Coastal Zone, which is divided into three separate areas(The Grand Strand, Santee River Delta, and the Barrier Islands), The second part going inland is the Coastal Plains, often divided into the Outer and Inner Coastal Plains, is also known as the Lowcountry. The land above the plains is known as the sandhills, which used to be South Carolina's fall line. Above that is the piedmont, which contains many major cities and is hilly. The last region is the Blue ridge, which is the smallest region. It is mountainous. The Lowcountry is nearly flat and composed entirely of recent sediments such as sand, silt, and clay. Areas with better drainage make excellent farmland, though some land is swampy. The coastline contains many salt marshes and estuaries, as well as natural ports such as Georgetown and Charleston. An unusual feature of the coastal plain is a large number of Carolina bays, the origins of which are uncertain, though one prominent theory suggests that they were created by a meteor shower. The bays tend to be oval, lining up in a northwest to southeast orientation.