This O’Rourke stronghold earned its place in history in 1487 when it became the first Irish castle to face cannon fire; a pioneering moment in siege warfare that would forever change how fortifications were built and battles were fought. The castle met destruction again in 1536, though it appears to have been refurbished when Tiernan Mac Owen O’Rourke received a land grant for the Manor of Carra in the early 1620s.

The castle sits on a natural defensive position, a rock platform roughly 30 metres north to south and 15 metres east to west, rising up to 2 metres above the valley floor. A small stream runs along its eastern edge, providing both a water source and an additional natural barrier. What remains today is a rectangular three-storey structure measuring 13.4 by 9.5 metres externally, though only the western gable wall and portions of the north and south walls still stand. The construction shows typical medieval Irish tower house features: randomly coursed limestone masonry, dressed corner stones (mostly robbed over the centuries), and a protective base batter to deflect projectiles.

The surviving architecture reveals how the castle evolved over time. The ground floor preserves its original defensive character with narrow single lights flanking a central fireplace in the west wall, and crucially, a gun loop beneath a small window in the south wall; evidence that the O’Rourkes adapted their defences after experiencing cannon fire firsthand. The upper floors show later modifications, with inserted two-light windows featuring square hood mouldings, suggesting attempts to make the fortress more comfortable as a residence. The absence of a barrel vault, typical of many Irish tower houses, and the direct insertion of floor joists into the walls hint at either cost-cutting measures or hasty reconstruction after one of its destructions.