Castle Pinckney, Military fort in Charleston Harbor, United States

Castle Pinckney is a circular masonry fortification on Shutes Folly Island, roughly one mile (1.6 kilometers) off the Charleston coast in South Carolina. The structure rises directly from the water and encloses an open courtyard with casemates along the outer wall.

The fortification was completed in 1810 on the site of an earlier defense work and followed a new concept for American harbor protection. It became the first Federal installation seized by South Carolina forces in December 1860, shortly before the outbreak of the Civil War.

The fort is named after Charles Cotesworth Pinckney, a Revolutionary War officer and South Carolina statesman. Its brick rondell forms slightly more than a half circle, closed at the rear by a hollow traverse that served as a defensive barracks. Two half-round flanking works guard the entrance, and the guns stood in the upper casemate tier. The site is closed and cannot be entered.

The fort is closed and cannot be visited; the German source states plainly that access is not possible. The structure stands on Shutes Folly about 1.7 km east of Charleston, and its masonry is exposed to the harbor and deteriorating. The site can be viewed only from the water or from a distance.

The fortification is one of the few remaining American coastal defenses from before 1820 that still shows its original horseshoe layout. Despite its small size, its position in the harbor allowed it to control strategically important shipping lanes.