Fort Phoenix retains a parapet built before the Civil War and a gunpowder magazine completed in 1865, while the Civil War-era officer's quarters and barracks were destroyed by fire in 1918. Its parapet has an irregular shape that follows the contours of the promontory overlooking the harbor. The parapet's exterior walls are brick covered with cement and topped with a single row of tapered granite slabs, while the interior walls are made of smooth granite blocks with soil borrow material filling the space between them. Five large cannons are 24-pound cast-iron guns dated 1828 that were mounted there about 1861, and a small naval cannon is the only gun dating to the Revolutionary War, having been brought there in 1777 from weapons captured from the British in the Bahamas. The cannons are ceremonially fired during the Town's annual Independence Day celebrations. In 1926, the Town of Fairhaven acquired Fort Phoenix from the United States Government through the generosity of Cara Broughton, daughter of Henry Huttleston Rogers, and it was placed on the National Register of Historic Places in 1973. The Town of Fairhaven Board of Public Works and the Fairhaven Historical Commission now maintain it.