This seventeenth-century fortified house, with its distinctive Z-plan layout and pear-shaped angle towers, may have begun life as Derry Castle or DerrymcEgan Castle before being refortified around 1650, possibly by Henry Ireton during the Cromwellian period. The confusion deepens thanks to old Ordnance Survey maps from the 1840s, which placed Ireton’s Castle near Belle Isle House where a nineteenth-century windmill stands today; though it’s equally possible the windmill was simply built atop the castle’s original site.

The building itself is a robust example of mid-seventeenth-century defensive architecture, constructed from roughly coursed limestone rubble. Its central rectangular block spans 7.5 metres east to west and 6.3 metres north to south, with walls an impressive 1.6 metres thick. What makes this fortified house particularly striking are its spear-shaped angle towers at the northeast and southwest corners, each built in two distinct phases: a three-storey circular tower base with a two-storey triangular projection added on top, creating that distinctive pear shape. The triangular sections, accessed through flat-headed doorways at second-floor level, give the structure the appearance of a hybrid between a traditional fortified house and the star-shaped artillery forts that were becoming popular during this period.

The defensive features reveal the serious military purpose behind this elegant design. A round-arched doorway on the western wall, protected by an overhead murder hole, provides the only ground-level access. Gun loops pierce the angle towers at first and second-floor levels, whilst bartizans supported on finely cut stone corbels crown the towers at wall-walk level. The interior preserves evidence of comfortable living quarters too; fireplaces warm the first and second floors, with a handsome rectangular chimney stack emerging from the northeast angle. A two-storey fore-building against the western face may be original or a later addition, whilst remnants of the bawn wall run from the northeast tower, now incorporated into nineteenth-century farm buildings. The architectural similarities to Kilcolgan fortified house in County Offaly, which bore a datestone of 1649, support the theory that Ireton’s Castle emerged during those turbulent years of the Cromwellian conquest.