Dating likely from the late 16th or early 17th century, this impressive structure consists of a central block flanked by two towers of unequal height; the western tower rises four storeys whilst its eastern counterpart reaches only three. The architect displayed considerable ingenuity in the design, angling the front of the house so that windows in the main block could catch sunlight that would otherwise be blocked by the projecting towers. The main entrance, located on the eastern wall of the western tower, features finely dressed limestone work with a two-centred doorway that still shows evidence of its original defensive features, including a yett hole and hanging eye for securing heavy doors, all protected from above by a machicolation at wall-walk level.

The castle’s defensive perimeter, or bawn wall, partially survives on the eastern side, complete with two corner towers at the northeast and southeast positions. Both towers, measuring 4.3 metres in external diameter with walls 0.8 metres thick, rise two storeys and feature gun loops at each level, demonstrating the transition from medieval arrow slits to early modern firearms defence. The towers retain evidence of wall-walks at roof level, from where defenders could patrol and survey the surrounding marshlands. Whilst the southern and western sections of the bawn have vanished over the centuries, what remains provides a clear picture of how seriously the castle’s builders took their defensive responsibilities.

Inside, traces of the castle’s domestic arrangements survive despite centuries of decay. The western tower preserves a large fireplace at fourth-floor level with its rectangular chimney stack still visible above, whilst below sits a small round-headed window complete with its original slop stone for drainage. A spiral staircase, now destroyed, once connected the tower’s entrance to the main rooms of the central block, where two large windows at first-floor level, though now ruined, would have illuminated the principal chambers. These architectural details, from the punch-dressed limestone of the doorway to the practical placement of gun loops, reveal Ballymooney as a fascinating example of the fortified houses built during Ireland’s turbulent transition from medieval to early modern times, when comfort and defence went hand in hand.