Fort Moultrie Fort Moultrie is the name of a series of citadel s 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 . History . American Revolution . South Carolina patriots began to build a fort to guard Charleston , South Carolina , harbor in 1776 . British Admiral Sir Peter Parker with nine British warships attacked the fort — still unnamed and incomplete — on June 28 , 1776 , near the beginning of the American Revolutionary War . The soft palmetto logs did not crack under bombardment but rather absorbed the shot ; cannonballs reportedly even bounced off the walls of the structure . William Moultrie , commander of the 2nd South Carolina Regiment , and his four hundred men fought a day - long battle that ended with the heavily damaged British ships being driven from the area . This victory galvanized the Patriots ' cause for independence . The fort hence took its name Fort Moultrie in his honor . Charleston locals celebrate " Carolina Day " to commemorate the bravery of the defenders of the fort . During this battle , the Moultrie flew a flag of his own design , authorized by the colonial government . It was later called the Moultrie flag or Liberty flag and became iconic to the Revolution in the South . The British eventually captured Fort Moultrie as part of the Siege of Charleston in spring 1780 . Nevertheless , the colonists won the war , and British troops departed in 1782 , at which time the flag was presented in Charleston , by General Nathanael Greene , commander of the southern Regulars . Early federal period . Great Britain and France began another war in 1793 , heightening tensions . The United States of America thence embarked on a systematic fortification of important harbors . Atop the decayed original Fort Moultrie , the Army completed a new fort in 1798 ; the Army also built nineteen other new forts along the Atlantic coast . A hurricane destroyed Fort Moultrie in 1804 , and a brick fort , the third and last such structure , replaced it in 1809 . It had five hundred men in the garrison . Fort Moultrie changed little over the next five decades . The Army altered the parapet and modernized the armament , but defense of Charleston centered increasingly around newly created Fort Sumter . By the time of the American Civil War , Fort Moultrie , Fort Sumter , Fort Johnson , and Castle Pinckney surrounded and defended Charleston . Fort Moultrie began to record meteorological observations in the early 1820s . The Army detained Seminole Indian fighter Osceola and some fellow Seminole prisoners at Fort Moultrie late 1837 . Osceola died of malaria in January 1838 ; the Army buried his corpse at Fort Moultrie and thereafter maintained his grave . Civil War . In the months leading up to the Civil War John L . Gardner was in command at Fort Moultrie . With secession growing more imminent Gardner had made several requests to Secretary of War John B . Floyd for more troops to garrison and defend the undermanned fortress . Each time his requests were ignored as the soon to be traitor Floyd was planning to hand the forts in Charleston Harbor over to the secessionists . South Carolina seceded from the Union on December 20 , 1860 . Unlike their counterparts at the other forts , defenders of Fort Moultrie chose not to surrender to the South Carolina forces . On December 26 , 1860 , Union Major Robert Anderson moved his garrison at Fort Moultrie to the stronger Fort Sumter . On February 8 , 1861 , South Carolina joined other seceded Deep Southern states to form the Confederate States of America . In April 1861 , Confederate troops shelled Fort Sumter into submission and the American Civil War began . In April 1863 , Federal ironclad s and shore batteries began a bombardment of Fort Moultrie and the other forts around Charleston harbor . Over the ensuing twenty months , Union bombardment reduced Fort Sumter to a rubble pile and pounded Fort Moultrie below a sand hill , which protected it against further bombardment . The Rifled cannon proved its superiority to brickwork fortifications but not to the endurance of the Confederate artillerymen who continued to man Fort Moultrie . In February 1865 , the Confederate Army finally abandoned the rubble of Fort Moultrie and evacuated the city of Charleston . Postbellum period . The Army modernized Fort Moultrie in the 1870s with huge rifled cannon and deep concrete bunkers . Further modernization in the 1880s turned all of Sullivan ' s Island surrounding the old fort into a military complex . The fort evolved with the times through and beyond World War II . On August 15 , 1947 , the Army lowered Fort Moultrie ' s flag for the last time and ended 171 years of service . After the war , seacoast defense of the United States ceased to be a viable strategy . Decommissioning . The Department of Defense in 1960 turned Fort Moultrie to National Park Service . NPS manages the historic fort as a unit of Fort Sumter National Monument . NPS constructed the fort as a tour backward in time through its defenses from World War II to the original palmetto log fort constructed by William Moultrie . The National Register of Historic Places listed Fort Moultrie Quartermaster and Support Facilities Historic District on September 6 , 2007 . In 2016 , the " America the Beautiful " quarter for South Carolina will feature " Fort Moultrie ( Fort Sumter National Monument ) . " Moultrie is honored with his statue in The Battery section of downtown Charleston .