Fort Wagner or Battery Wagner was a beachhead fortification on Morris Island, South Carolina, that covered the southern approach to Charleston Harbor. It was the site of two American Civil War battles in the campaign known as Operations Against the Defenses of Charleston in 1863, in which United States forces took heavy casualties while trying to seize the fort.

Morris Island is an 840-acre (3.4 km2) uninhabited island in Charleston Harbor in South Carolina, accessible only by boat. The island lies in the outer reaches of the harbor and was thus a strategic location in the American Civil War. The island is part of the cities of Charleston and Folly Beach, in Charleston County.