This thesis examines the landscape evolution of the one hundred and twenty year history of Fort Moultrie Military Reservation (FMMR), Sullivan's Island, South Carolina, one of the United States' Twentieth Century coastal defense installations. During the first half of the century, these technologically advanced fortifications protected the country's coasts as the nation emerged as a world power. When World War II's technological advances made these installations' obsolete, most were quickly converted into new military or government operated public uses. The remainder, including FMMR, was sold after the war to the public, before the limited protections of the National Historic Preservation Act of 1966 were implemented. As a result over the past sixty-five years, the majority of FMMR has been rehabilitated for individual residents' use with little understanding of their overall historical significance. This division of ownership between its private residents and remaining government owners has altered many of the installation's significant features and obscured the island's military origins from its current population. This analysis uncovers these forgotten pieces of island history, by examining the installation's growth during four major historical periods through the lens of the National Park Service's and the U.S. Army Environmental Command's cultural landscape guidelines. Next, by understanding why and how the base became part of the island's modern residential community, a current survey of FMMR's enduring features showcases the broad effects the military landscape had on Sullivan's Island's recent development. By understanding FMMR's historic milestones and their relevance, recommendations that protect and showcase these forgotten landscape features can emphasize the island's history and strengthen its unique sense of place.