Stack Rock Fort

Stack Rock Fort is an island fort built in two parts, featuring a gun tower constructed in 1850 from tooled grey limestone. The tower is two storeys high and has a trefoil plan with rounded elevations, a coped parapet, and a flat roof. It is completely surrounded by an added ring made of rock-faced limestone and silver granite. This ring includes casemates for guns, which occupy three-quarters of the circle, and a recessed two-storey block on the north side that matches the roof line of the tower. The inner tower is not visible from the exterior.

The casemates have sixteen large, deeply-recessed cambered-headed openings fitted with iron shutters, while the recesses themselves feature square-headed designs. The masonry is composed of large square blocks with raised coping, and the base is made of smaller rock-faced blocks that slope outward in the lower half. There is a bull-nose string course below the casemates, and the flat roof includes concrete gun emplacements. The ends of the casemate ring are rounded and lead into the two-storey north range, which has a curved three-bay front with widely spaced small square windows and a centrally located square-headed door, elevated above a high battered plinth.

The interior is not accessible, but the rear of the two-storey north range features brick walls with broad cambered-headed openings, which are glazed with small panes and include mullions and a transom. An iron balcony provides access to the upper floor.