The original Palmetto log fort was begun in 1776 and only partially completed when attacked by a squadron of British warships. Col. William Moultrie and his men staved off the assault in the Battle of Sullivan's Island.
The current structure was completed in 1809. Union soldiers abandoned the fort in December 1860 for the stronger Fort Sumter. Following the surrender of Fort Sumter, Confederate forces fortified Moultrie as one of a string of batteries and forts protecting Charleston's harbor. In February 1865, Confederates evacuated the city leaving the fort behind, hidden under a band of sand that protected its walls from federal shells. The interior of the fort has been restored to reflect the story of American seacoast defense through World War II, and a visitor center is located near the fort. An "African Passages" exhibit deals with the role of Sullivan's Island and the international slave trade. The National Park Service administers the fort. School groups admitted free.