South Carolina is a state in the Southern region of the United States. It is bounded 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. There are four geographic areas in South Carolina, whose boundaries roughly parallel the northeast/southwest Atlantic coastline. The lower part of the state is the Coastal Plain, also known as the Lowcountry, which is nearly flat and composed entirely of recent sediments such as sand, silt, and clay. The coastline contains many salt marshes and estuaries, as well as natural ports such as Georgetown and Charleston.
Just west of the coastal plain is the Sand Hills region, which is thought to contain remnants of old coastal dunes from a time when the land was sunken or the oceans were higher. Highest in elevation is the Upstate, containing an escarpment of the Blue Ridge Mountains, which continue into North Carolina and Georgia, as part of the southern Appalachian chain.
South Carolina has a humid subtropical climate, although high elevation areas in the "Upstate" area have less subtropical characteristics than areas on the Atlantic coastline. In the summer, South Carolina is hot and humid. The winter temperatures are much less uniform. Coastal areas of the state have very mild winters. Further inland in the higher country, the average low can be below freezing. Precipitation is abundant the entire year in almost the entire state but the coast tends to have a slightly wetter summer. March tends to be the wettest month.