Once owned by the Fitzpatricks, Lords of Upper Ossory, this limestone tower house met its demise in 1600 when it was deliberately burned down to prevent English forces from converting it into a garrison. Today, only partial remains survive: sections of the northeast and southwest walls, along with a northeast angle tower, all constructed from uncoursed rubble limestone with a slight base batter. The most notable surviving features include evidence of a barrel-vaulted entrance running northeast to southwest, and a large splayed opening at first-floor level in the northeast wall.

The castle’s unusual proportions have intrigued historians for over a century. Writing in 1905, Carrigan described it as “a very curious old building”, noting its external length of 45 feet but remarkably narrow internal width of just 12 feet. The structure featured a projection at the northeast corner that was rectangular at its base but rounded above. To reinforce the west wall, builders had constructed an additional wall of equal thickness against the outside, effectively doubling its strength. The walls themselves ranged from 3.5 to 4 feet thick, with the east wall reaching a height of 30 feet before the castle’s destruction.

Perhaps the most impressive surviving element is the bawn wall attached to the southeast angle, which enclosed an almost circular defensive area. This wall, measuring approximately 1.1 metres thick and featuring a series of gun loops, stands up to 3 metres high in places with evidence of a wall walk along its length. Archaeological surveys from 1994 revealed that the bawn was irregular in shape, possibly octagonal, composed of at least four sections of straight-sided walls. The enclosed area measured roughly 65 metres northeast to southwest and 41 metres northwest to southeast. Four gun loops pierce the wall, with two positioned at a point where the wall changes direction sharply; a testament to the defensive considerations of its builders. According to Carrigan, both the castle and its courtyard were originally surrounded by a deep fosse, adding another layer of defence to this frontier stronghold.