Martello towers were a widespread British coastal defence measure, built in large numbers along Irish and British shorelines during the Napoleonic period to counter the threat of French invasion. This example rises to around seven metres, tapering gently as it goes, and its internal ground plan is almost perfectly circular, measuring just over six metres across in both directions.

The design details here are precisely those that made Martello towers so effective as defensive structures. The entrance door sits at first-floor level on the eastern face, with a machicolation directly above it, an opening in the projecting stonework through which defenders could drop objects or fire down on anyone attempting to force the door. A spiral staircase on the first floor leads up to the roof, where a mural chamber is set into the parapet wall and the gun-carriage track runs around the wall-walk. The vaulted roof over the first floor runs on an east-west axis. Splayed windows, wider on the inside than the outside to allow a broader field of view and fire, open to the northwest and southwest. Just to the south of the tower are the remains of a rectangular structure, and to the northeast, roughly a third of a metre away, lies an ordnance ground with the remains of an associated battery, indicating that this was once part of a more extensive defensive installation rather than an isolated outpost.