Whilst historian Peter Harbison dates the current structure to the early 14th century, the castle’s lower sections likely incorporate remnants of the original stronghold built by the de Bermingham family around 1225. The building underwent significant reconstruction in the late 16th or early 17th century, when builders added an extra floor to create the imposing five-storey rectangular keep that survives today, measuring 14 metres long and 8.2 metres wide with dramatically sloping battered walls.

The castle’s architecture reveals its complex history through various structural modifications. The original entrance, now robbed of its stonework, was positioned at first-floor level on the southern end of the east wall, with two beam holes below marking where an external wooden staircase once provided access. A later doorway was inserted at ground level directly beneath this original entrance, which now serves as the main access point. Inside, a broken spiral staircase in the northeast corner connects the ground and first floors, whilst the absence of stone vaulting suggests the floors were originally supported by timber beams. The internal walls still show traces of the original gable lines between the second and third floors, evidence of the castle’s earlier, more modest height.

The interior features reflect centuries of domestic occupation, with fireplaces strategically placed throughout: in the north wall on the first and second floors, the east gable on the second and third floors, and the west gable on the third floor. A garderobe in the northwest corner on the first floor provided medieval sanitation, whilst slop-stones at parapet level on the north, east, and south walls allowed for waste disposal. The surviving windows range from a circular oculus on the third floor of the north wall to two mullioned windows with decorative hood mouldings in the south wall, alongside numerous rectangular defensive slits. This National Monument, taken into state ownership under the National Monuments Acts and designated as National Monument 248, stands as a remarkable example of how Irish tower houses evolved over centuries to meet changing defensive and domestic needs.