The four-storey structure at Abbeyshrule Castle measures just 5.8 metres east to west and 5.4 metres north to south, built from roughly coursed rubble that has weathered centuries of Irish weather. Though time hasn’t been entirely kind to the building; its southern and western walls have collapsed down to first-floor level, leaving only fragments of what was once a complete defensive residence.

The tower’s original entrance likely stood in the northern wall near the northeast corner, though fallen masonry now obscures this area. A partially collapsed spiral staircase winds up through this corner, cleverly designed to serve each floor via mural passages built into the thickness of the walls. The ground floor, now inaccessible, features a barrel vault overhead; a common defensive feature that provided both structural strength and fire resistance. Above, the eastern wall reveals the tower’s domestic character: a simple, flat-headed window opening at first-floor level, with a large fireplace positioned directly above it on the second floor. At battlement level, stone corbels jut from the same wall, once supporting a chimney stack that would have drawn smoke from the hearth below.

This residential tower likely dates to the late 16th century, built during the post-Dissolution period when many Irish monasteries were converted to secular use following Henry VIII’s break with Rome. Rather than abandoning the abbey entirely, new occupants repurposed the sacred grounds, adding this defensive tower house amongst the medieval religious buildings. It stands as a physical reminder of how Ireland’s ecclesiastical landscapes were dramatically transformed during the Tudor conquest, when abbeys became castles and monks’ quarters became lords’ lodgings.