Fort Moultrie, Military fort and museum on Sullivan's Island, South Carolina, US.

Fort Moultrie is a fortified position on Sullivan's Island in South Carolina along the Atlantic coast near Charleston. The site includes bastions from different construction phases, underground corridors, and exhibition rooms about American coastal defense.

The first structure built with palmetto trunks appeared in 1776 and repelled British naval assaults, protecting Charleston from capture. Later expansions took place during the Civil War and both World Wars, when defense technology underwent fundamental changes.

The coastal position today displays artillery emplacements from multiple eras and interpretation panels about the region's military defense story. Visitors can trace how coastal fortification technology changed over two centuries.

Fort Moultrie is managed by the National Park Service as part of the Fort Sumter and Fort Moultrie National Historical Park. The site sits at the southern tip of Sullivan's Island beside the harbor entrance, with stairs and metal railings linking the different levels of the earthwork. Visitors move between the concrete bunker, the curved wall around the arched entry and the row of roof panels set into the grass.

The soft palmetto trunks of the first wooden fortification absorbed British cannonballs instead of shattering, contributing significantly to the defense. This unusual building material later became the symbol of South Carolina and now appears on the state flag.