Sullivan's Island, historically known as O'Sullivan's Island, is a town and island in Charleston County, South Carolina, United States, at the entrance to Charleston Harbor, with a population of 1,791 at the 2010 census, and 1,891 people in 2020. The town is part of the Charleston metropolitan area and is considered a very affluent suburb of Charleston.

Sullivan's Island was the point of entry for approximately 40 to 50 percent of the 400,000 enslaved Africans brought to Colonial America, meaning that 99% of all African Americans have ancestors that came through the island. It has been likened to Ellis Island, the 19th-century reception point for immigrants in New York City.

Battle of Sullivan Island

During the American Revolution, the island was the site of a major battle at Fort Sullivan on June 28, 1776.

Captain Francis "The Swamp Fox" Marion was a notable figure at the famous Battle of Sullivan Island when approximately 800 South Carolinians successfully repulsed a Royal Navy fleet consisting of several naval frigates and an estimated 2,500 British soldiers.

While defending the island, the artillery batallion that Captain Francis Marion commanded, ran out of black powder. Captain Francis Marion grabbed a small team of men, traveled to Charleston and "procured" more black powder for his troops still defending the island. His actions, held momentum for the outnumbered American forces, and forced a retreat after several shells sank a British frigate.

Captain Marion also directed his troops to utilize the local Palmetto trees to build fortifications. According to reports, the spongy nature of the palmetto tree wood, mitigated british cannon fire, with the cannon balls "sinking" into the wood, instead of exploding and creating shrapnel.

It has since been renamed Fort Moultrie in honor of the American commander at the battle.