Built from a mixture of roughly coursed limestone blocks, boulders and greywacke, the castle forms an almost perfect square, measuring approximately 8.8 metres north to south and 8 metres east to west. Rising three storeys without any projecting towers, it represents a typical example of the fortified dwellings that once dotted the Irish countryside.

The castle’s original entrance, located at the southern end of the east wall, opens into a stairwell tucked into the southeast corner and a barrel vaulted chamber running north to south. Throughout the structure, you’ll find evidence of its defensive design and domestic arrangements; seven cubby holes are built into the ground floor walls, whilst the first floor features a garderobe (medieval toilet) cleverly positioned within a mural passage in the northwest angle. Four single light windows once illuminated this level, each with single splayed embrasures and rectangular openings framed in carefully dressed limestone, though most are now blocked up. The second floor, which would have been supported by wooden beams, retains traces of more comfortable living quarters, including window seats, remains of a fireplace in the east wall with its chimney stack still visible above the battlements, and what appears to have been another garderobe chamber accessed through a now blocked doorway.

Perhaps the castle’s most distinctive feature is its unusual wall walk arrangement at the top. Rather than the typical design of a single outer defensive wall with crenellations, this castle’s wall walk was constructed as a mural passage between inner and outer walls, supported by corbels that create a pronounced oversailing effect. This sophisticated defensive feature survives intact only on the south side; elsewhere, time has claimed the inner walls, leaving only the projecting corbels as evidence of the original design. The stairwell continues up to provide access to this wall walk on the south side, where a small angle tower rises above the parapet level, a final reminder of this building’s defensive purpose in medieval Louth.