Hanahan is a city in Berkeley County, South Carolina, United States. The population was 12,937 at the 2000 census. The 2010 census puts the population at 17,997. Portions of the Naval Weapons Station Charleston, including the Naval Consolidated Brig Charleston, are located in Hanahan. As defined by the U.S. Office of Management and Budget, and used by the U.S. Census Bureau for statistical purposes only, Hanahan is included within the Charleston-North Charleston-Summerville metropolitan area and the Charleston-North Charleston Urbanized Area.