The castle's most striking feature is its massive three-storey tower house, complete with corner towers, which forms the heart of the southern range. Connected to this medieval core by a battlemented wall is a fine gatehouse, whilst a two-storey hall from the 17th century extends eastward from the tower house. The castle underwent significant transformation in the early 18th century when William St. Lawrence modernised and enlarged the structure, adding classical style alterations to the central hall that reflected the changing architectural tastes of the period.

The tower house itself reveals layers of history in its construction details. The ground floor, measuring 6.77 metres in length and 5.60 metres in width, features an unusual dual vault with an intervening wall, accessed today through a later partition that creates a corridor within the original chamber. A spiral stairway housed in a square projecting tower at the northwest angle connects the floors, though later renovations have seen these stairs replaced and unfortunately cut across the original window openings. The second floor, entered through a pointed arch doorway, retains more of its medieval character with window openings in the east and south walls, and a corbelled recess in the southwest angle tower lit by a single slit loop. At battlement level, a wall walk connects four projecting angle towers, with the whole structure topped by a double-pitched slate roof set behind a distinctive crow-stepped crenellated parapet.

Throughout the castle grounds, fragments of earlier architectural elements tell their own stories; a carved dragon has been built into the garden entrance wall, whilst a 16th-century inscribed tablet marks the entrance to the stable yard north of the castle. These details, along with features like the squinch in the southeast corner that once supported a corner tower, showcase the continuous evolution of this important Irish fortification from its medieval origins through centuries of adaptation and modernisation, with the most recent re-rendering work carried out around 1990.