Built around 1621 by Lord Barrymore to celebrate his marriage to Alice Boyle, daughter of the Earl of Cork, this once magnificent estate has endured centuries of misfortune. What remains today are two distinct sections: medieval foundations to the south, and 17th-century ruins to the north that once formed part of a grand square building with a central courtyard. The structure met its demise in an accidental fire on 22 July 1771, and subsequent quarrying has left it in its current fragmentary state.

The surviving northern ruins reveal the castle’s former splendour through their elaborate architectural details. Three massive chimney stacks dominate the remains, two projecting from the north wall and one crowning a dividing wall, each topped with diagonally-set conjoined shafts and decorative cornices. The main rectangular block once stood three storeys tall with an attic and eastern basement, containing fireplaces at each level including a particularly large one with flanking bread ovens. A rock-cut drain in the northwest corner may have served as an inlet for the aqueduct mentioned in historical records. To the north, a substantial terrace stretches 54 metres long, whilst an ornamental tower stands nearby, likely part of the elaborate gardens that once featured a large canal to the west, now evidenced only by two round-arched bridges.

The castle’s military significance becomes apparent in its defensive features, particularly those added around 1641-42 when it served as an English stronghold during turbulent times. Remnants of what appear to be artillery fortifications can be traced along the terrace, matching depictions on the 1652 Down Survey map. To the south, a 40-metre section of heavily ivy-clad wall survives from what was probably the bawn, complete with the remains of stairs to a wall walk and what appear to be gun loops barely visible through the vegetation. These fortifications bear witness to the castle’s role in numerous engagements during the Confederate Wars, transforming what began as a romantic gesture into a strategic military position before its eventual destruction.