Named for President Adams, and originally planned as the centre of a defence complex protecting the entrance to Narragansett Bay, this fort was designed to defend against assault from both the land and the sea, and as such, mixed two distinct forms of military architecture.
Begun in the 1820's, the fort was never completed as conceived, due to the evolution of military armaments. Initially planned to house 468 guns, the fort was only ever armed with a fraction of that. With the destruction of Fort Pulaski in 1862, the grand era of the masonry fort was over, rendered obsolete by the punishing impact of rifled projectiles. During the Civil War, Fort Adams was rearmed with 10" and 15" Rodman guns. By the 1880's though, the US Corps of Engineers determined that the American Coastal Defences were obsolete and recommended the construction of modern concrete batteries. These sites, up and down the American section of the eastern seaboard, replaced the older fortifications like Fort Adams. It eventually became the World War II command centre for a large series of coastal forts from Long Island Sound to Northern Maine.
Designed using the principles of French military architecture, Fort Adams is unique in North America. Unlike many of its contemporaries, Fort Adams used extensive earthworks to the south of the fort to defend itself from land assault and stacked casemented emplacements along the western face of the fort to defend from the sea. These two elements combine to make Fort Adams' 1700 meter perimeter more understandable. These defences used not only gun positions but also listening tunnels, counter mines, and a separate Redoubt, to the south.
Fort Adams is preserved and administered by the Fort Adams Trust.