Known as Cabra Castle on Rocque’s 1775 map of Thurles, the structure measures roughly 6.76 by 6.2 metres and features walls 1.2 metres thick, built from roughly coursed limestone blocks. The tower’s base displays a characteristic defensive batter on three sides, though curiously not on the northwest face, and nineteenth century alterations are evident in the crudely hammered quoins at the eastern corner.

The interior reveals a complex arrangement typical of tower houses, with the original entrance at the north end of the northeast wall leading to a passage containing an alcove and access to both a barrel vaulted ground floor chamber and a narrow mural staircase. The stairs, measuring just 60 centimetres wide, wind up through the northwest wall before turning southeast. Various architectural features hint at the building’s long history of modification; blocked doorways pierce the northwest wall at first floor level, whilst a triangular hole of unknown purpose sits mysteriously in the passage roof. The first floor chamber, covered in lime plaster and topped with a barrel vaulted stone ceiling, receives light through three single windows and contains a built in wall cupboard. According to OS Letters from the 1930s, the structure once featured a possible bartizan or watch tower at the northwest angle, though today the tower survives only to first floor level, its upper portions having been neatly removed.

Approximately 20 metres north of the tower house, a substantial limestone wall stretching 22.2 metres may represent the remains of a bawn, the defensive courtyard typical of Irish tower houses. Standing 2.5 metres high with cemented coping that appears to incorporate brick, the wall features a defensive batter on its southeast face and is supported by two large buttresses on the northwest side where significant bulging has occurred. Foundation stones at the northwest end suggest the wall originally turned to meet the tower house itself, creating an enclosed defensive space that would have offered additional protection to this riverside stronghold.