South Carolina ( KARR-ə-LY-nə) is a state in the Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia to the west and south across the Savannah River. Along with North Carolina, it makes up the Carolinas region of the East Coast. South Carolina is the 40th-largest and 23rd-most populous U.S. state with a recorded population of 5,118,425 according to the 2020 census. In 2019, its GDP was $213.45 billion. South Carolina is composed of 46 counties. The capital is Columbia with a population of 136,632 in 2020; while its most populous city is Charleston with a 2020 population of 150,227. The Greenville-Spartanburg-Anderson, SC Combined Statistical Area is the most populous combined metropolitan area in the state, with an estimated 2023 population of 1,590,636.

South Carolina derives its name from King Charles I of England, who was instrumental in establishing the English colony, with Carolus being the Latin equivalent of "Charles". The Province of South Carolina was officially created in 1712. As one of the original Thirteen Colonies, it transitioned to a royal colony in 1719. Throughout the American Revolutionary War, South Carolina witnessed significant military engagement, hosting over 200 battles and skirmishes. On May 23, 1788, South Carolina became the eighth state to ratify the U.S. Constitution. As a slave state, it was the first to vote for secession from the Union on December 20, 1860. Following the American Civil War, South Carolina was readmitted to the Union on July 9, 1868.

In the early to mid-20th century, South Carolina experienced significant economic development with the establishment of numerous textile mills and factories throughout the state. The civil rights movement during the mid-20th century played a crucial role in dismantling segregation and discriminatory laws in the state. Following World War II, South Carolina's economic diversification accelerated, leading to a broader range of industries. By the early 21st century, the state's economy had evolved to include sectors such as aerospace, agribusiness, automotive manufacturing, and tourism.

South Carolina features three primary geographic regions stretching from east to west: the Atlantic coastal plain, the Piedmont, and the Blue Ridge Mountains located in the northwestern part of Upstate South Carolina. The state predominantly experiences a humid subtropical climate characterized by hot, humid summers and mild winters. In the Upstate region, the climate shifts to a subtropical highland type. The eastern coastal plain is dotted with numerous salt marshes and estuaries. The southeastern Lowcountry of South Carolina includes parts of the Sea Islands, a series of barrier islands along the Atlantic Ocean.