Charleston is the oldest and largest city in the U.S. state of South Carolina, the county seat of Charleston County, and the principal city in the Charleston–North Charleston–Summerville Metropolitan Statistical Area.The city lies just south of the geographical midpoint of South Carolina's coastline and is located on Charleston Harbor, an inlet of the Atlantic Ocean formed by the confluence of the Ashley, Cooper, and Wando rivers. Charleston had an estimated population of 134,875 in 2017. The estimated population of the Charleston metropolitan area, comprising Berkeley, Charleston, and Dorchester counties, was 761,155 residents in 2016, the third-largest in the state and the 78th-largest metropolitan statistical area in the United States.

Charleston was founded in 1670 as Charles Town, honoring King Charles II of England. Its initial location at Albemarle Point on the west bank of the Ashley River (now Charles Towne Landing) was abandoned in 1680 for its present site, which became the fifth-largest city in North America within ten years. Despite its size, it remained unincorporated throughout the colonial period; its government was handled directly by a colonial legislature and a governor sent by London. Election districts were organized according to Anglican parishes, and some social services were managed by Anglican wardens and vestries. Charleston adopted its present spelling with its incorporation as a city in 1783 at the close of the Revolutionary War. Population growth in the interior of South Carolina influenced the removal of the state government to Columbia in 1788, but the port city remained among the ten largest cities in the United States through the 1840 census. Historians estimate that "nearly half of all Africans brought to America arrived in Charleston", most at Gadsden's Wharf. The only major antebellum American city to have a majority-enslaved population, Charleston was controlled by an oligarchy of white plantersand merchants who successfully forced the federal government to revise its 1828 and 1832 tariffs during the Nullification Crisis and launched the Civil War in 1861 by seizing the Arsenal, Castle Pinckney, and Fort Sumterfrom their federal garrisons.

Known for its rich history, well-preserved architecture, distinguished restaurants, and hospitable people, Charleston is a popular tourist destination. It has received numerous accolades, including "America's Most Friendly [City]" by Travel + Leisure in 2011 and in 2013 and 2014 by Condé Nast Traveler, and also "the most polite and hospitable city in America" by Southern Living magazine. In 2016, Charleston was ranked the "World's Best City" by Travel + Leisure.