What remains of this once formidable square tower house, measuring approximately 7.6 metres north to south and 6.8 metres east to west externally, offers just enough detail to piece together its original grandeur. The castle’s thick walls, at 1.4 metres, once supported multiple floors connected by a spiral staircase in the south-east corner, though this has long since crumbled away. When documented in 1841, the structure was already in an advanced state of ruin, with its east side reduced to foundations and much of the north wall collapsed.

The internal dimensions, recorded as 4.8 metres east to west and 4 metres north to south, reveal the compact living space typical of Irish tower houses. Stone arches once supported the second and fourth floors, though only fragments remained even in the nineteenth century. Of the castle’s original windows, just two survived relatively intact by 1841: a narrow rectangular opening on the south wall that once illuminated the first floor, and another on the west wall serving the fourth floor. These sparse architectural details hint at the defensive nature of the structure, with its small windows designed more for security than comfort.

Perhaps most intriguingly, the castle has suffered further indignities since its nineteenth-century documentation. Past quarrying activities have dramatically altered the landscape, truncating both the castle site and its surrounding earthworks by up to ten metres. Whilst the quarry face has since become overgrown with scrub, suggesting the industrial work ceased some time ago, the damage to the archaeological context is permanent. Some consolation exists in the fact that architectural fragments from the castle have found new life, incorporated into a house south of the old quarry site, ensuring that at least some physical memory of Ballymacadam Castle persists in the local landscape.