Hanahan is a city in Berkeley County, South Carolina, United States. The population was 12,937 at the 2000 census.

Hanahan is located on the very south end of Berkeley County, and its city limits on the west and south sides are contiguous with the county line between Berkeley and Charleston Counties. It was incorporated as a city in 1972.

Hanahan is bordered on the west and south by the city of North Charleston, South Carolina. To the east is the old Naval Weapons Station, which was formerly a submarine base, and is still federal property. A very small portion of this federal base is actually in Hanahan's city limits. Among other uses of the former submarine base, the Naval Consolidated Brig is there, as is the Navy's Nuclear Power School. To the north is an unincorporated portion of Berkeley County.

The CSX Railroad has a main north-south track that runs along Hanahan's west city limit. Hanahan is primarily a residential city. It does have quite a number of major warehouses in the southeast portion of the city, most of whose business is tied directly to the Port of Charleston. There are relatively few commercial businesses for a city of its size. Practicing professionals include one medical doctor, five dentists, one veterinarian, three attorneys, an engineering firm, and a professional financial adviser.

The form of government is council-administrator. The council is the governing body of the city, with the city administrator being hired by, and serving at the pleasure of, the city council. The council and mayor are elected by the voters. The mayor is a first among equals on the council, presiding over council meetings and representing the city at official functions. The council hires and fires department heads. The mayor and council members, though paid a small salary, are not full-time, but are citizens with other jobs.

Most areas of Hanahan are located within a 10-15 minute drive of the major shopping area, including a regional mall (in North Charleston), in what is known locally as the "North Area." Also within a short drive are Interstate 26 and Interstate 526, as well as U.S. Highway 52.

The public schools in Hanahan are considered to be some of the best in the Tri-County Area (consisting of Berkeley, Charleston and Dorchester Counties).