Mount Pleasant is a large suburban town in Charleston County, South Carolina, United States. In the Lowcountry, it is the fourth-most populous municipality in South Carolina, and for several years was one of the state's fastest-growing areas, doubling in population between 1990 and 2000. The population was 90,801 at the 2020 census. It is part of the Charleston metropolitan area.

Charleston County is located in the U.S. state of South Carolina along the Atlantic coast. As of the 2020 census, the population was 408,235, making it the third-most populous county in South Carolina. Its county seat is Charleston. It is also the largest county in the state by total area, although Horry County has a larger land area. The county was created in 1800 by an act of the South Carolina State Legislature.