Johns Island, also spelled John’s Island, is the largest island in the U.S. State of South Carolina. It is the fourth largest on the U.S. east coast, surpassed only by Long Island, Mt Desert Island, and Martha’s Vineyard. Johns Island is 84 square miles (220 km2) in area, with a population of 14,000 people. Johns Island was named after St. John’s Parish in Barbados by the first settlers to the island. It is home to the Angel Oak, one of the oldest living trees in the United States, and countless farms that feed the Charleston area. Rural Charleston at its finest!