Fort Moultrie is the name of a series of citadels on Sullivan's Island, South Carolina, built to protect the city of Charleston, South Carolina. The first fort, built of palmetto logs, inspired the flag and nickname of South Carolina, "The Palmetto State". It is named for the commander in the Battle of Sullivan's Island, General William Moultrie. Fort Moultrie is the only area of the National Park System where the entire 171-year history of American seacoast defense (1776–1947) can be traced.