Mount Pleasant is a large suburban town in Charleston County, South Carolina, United States. It is the fourth largest municipality and largest town 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 67,843 at the 2010 census, and the estimated population in 2014 was 77,796. Mount Pleasant is the third largest city in the Charleston ? North Charleston ? Summerville metropolitan area, behind Charleston and North Charleston.