Wadmalaw Island is an island located in Charleston County, South Carolina, United States. It is one of the Sea Islands, a chain of tidal and barrier islands on the Atlantic Ocean. Wadmalaw Island is located generally to the southwest of Johns Island and more than halfway encircled by it. To the north it is bordered by Church Creek; to the nor…Wadmalaw Island is an island located in Charleston County, South Carolina, United States. It is one of the Sea Islands, a chain of tidal and barrier islands on the Atlantic Ocean. Wadmalaw Island is located generally to the southwest of Johns Island and more than halfway encircled by it. To the north it is bordered by Church Creek; to the northeast and east by Bohicket Creek; to the south by the North Edisto River; and to the west by the Bohicket Creek. The island's only connection to the mainland is via a bridge over Church Creek. The island is about 10 miles long by 6 miles wide. It has a land area of 108.502 km². The 2000 census reported a population of 2,611 persons.