Castle Pinckney

Castle Pinckney was a small masonry fortification constructed by the United States government in the 1790s in the harbor of Charleston, South Carolina.
Constructed on a shoal near the marshy Shutes' Folly Island a mile offshore from Charleston, the fort was meant to protect the city from a possible sea attack when war with France seemed imminent. The original log and earthen fort, named for the Revolutionary War hero Charles Cotesworth Pinckney, was completed in 1797. A severe hurricane in 1804 virtually destroyed it, and a replacement brick and mortar structure was erected in 1809.
As of 1851, it was intended to be armed with eight 42-pounder seacoast guns, ten 24-pounder guns, four 8" heavy seacoast howizters, one 10" heavy mortar, one 10" light mortar and one 8" light mortar, for a total of 25 guns.
It was used as a prisoner-of-war camp and artillery position during the American Civil War.