This rectangular tower, measuring 4.8 metres north to south and 8.9 metres east to west, was once part of a larger fortified complex belonging to the O’Driscoll clan. Remnants of a bawn wall can still be traced crossing the neck of the promontory to the west of the tower, including a heavily modified section that marks where the original gateway stood, complete with the ruins of a mural tower immediately to its north.

The castle has undergone significant changes since its medieval origins, having been converted into a farm building in more recent times, though it now stands disused. Currently rising to two storeys beneath a modern galvanised roof, the tower was originally taller. The ground floor entrance in the western wall has been blocked up, with a window in the northern wall now serving as the doorway. Inside, a modern wooden floor covers the ground level, but the original corbels and joist holes reveal where the medieval timber floor once sat. The first floor, accessed through a door in the western wall, contains several interesting architectural features: a mural passage on the south side leads to a narrow loop in the southwest corner, whilst another passage on the north side connects to a spiral staircase in the northwest corner. There’s also a small mural chamber built into the northern wall, entered from the window embrasure on the western side.

The castle’s turbulent history reflects the strategic importance of its harbour location. In 1537, citizens of Waterford attacked this O’Driscoll stronghold, and during the Nine Years’ War in 1601, Spanish forces garrisoned the castle as part of their ill-fated intervention in Ireland. Despite the modifications and damage sustained over the centuries, Dunalong Castle remains a protected monument under a preservation order, serving as a tangible link to the complex maritime and political history of West Cork.