Castle Pinckney, Charleston Harbor, Charleston, Charleston County, SC

Significance: The construction of Castle Pinckney began in 1809 on the site of the earlier fort. By 1811, it was ready for the installation of armaments. The design of Castle Pinckney is attributed to Jonathan Williams, the first superintendent of the United States Military Academy. Williams had served as secretary to Benjamin Franklin in France, where he studied the latest developments in military architecture. He was undoubtedly influenced by the theories of the Marquis de Montalembert, whose 1791 treatise on fortifications included a chapter on circular forts. Williams subsequently designed several circular forts for New York Harbor (called "castles" because of their evocation of medieval keeps), most notably Castle Clinton (1808), a near twin to Castle Pinckney, although built of stone.

Castle Pinckney was built of brick masonry construction, with its exterior walls approximately 15' in height and 7'-6" thick at the base. In plan, the fort was designed in the general shape of a "half-moon," with a 165' diameter. The sweeping, rounded section of the fort, oriented south toward the mouth of Charleston Harbor, contained eight casemates for cannons. Additional artillerty was to be mounted "en barbette" on the terreplein above. The straight section of the wall along the north side of the fort was flanked by two shallow, curved bastions, each with two levels of gun embrasures to provide protection for the centrally-located sally port. Barracks and officers' housing were located on the interior, along the north wall.
Unprocessed Field note material exists for this structure: N1666
Survey number: HABS SC-195
Building/structure dates: ca. 1809 Initial Construction
Building/structure dates: 1832 Subsequent Work
National Register of Historic Places NRIS Number: 70000574