Charleston County is located in the U.S. state of South Carolina along the Atlantic coast. As of the 2010 census, its population was 350,209, making it the third most populous county in South Carolina (behind Greenville and Richland counties). Its county seat is Charleston. The county was created in 1901 by an act of the South Carolina State Legislature.
Charleston County is included in the Charleston- North Charleston, SC Metropolitan Statistical Area.
Charleston-North Charleston, SC MSA
The Charleston metropolitan area is an area centered on Charleston, South Carolina. The U.S. Office of Management and Budget designates the area as the Charleston–North Charleston, SC Metropolitan Statistical Area, a metropolitan statistical area used for statistical purposes only by the United States Census Bureau and other federal agencies. The OMB defines the area as comprising Berkeley, Charleston and Dorchester counties, an area with 664,607 in the 2010 census (though a July 1, 2012 estimate placed the population at 697,439). Principal cities include Charleston, North Charleston, and Summerville. The area is commonly referred to as the Tri-County Area or the Lowcountry, though the latter term has historically referred to South Carolina coast in general.