The castle was already standing in 1574 when it belonged to Donell Ecowga O’Flaherty, a member of the powerful O’Flaherty clan who controlled much of Connemara. Local tradition holds that O’Flaherty built the tower himself, resourcefully recycling stones from the ruins of nearby Toombeola Abbey, though this tale of ecclesiastical plunder may be more legend than fact.

The original tower is remarkably small, measuring just 9.1 metres long and roughly 6.5 to 7 metres wide, yet it rises through four storeys with all the defensive features you’d expect from a medieval Irish tower house. The main entrance sits in the eastern wall, with a spiral staircase tucked into the southeast corner to connect the floors. The first floor even included an intramural latrine passage built into the southern wall; a practical luxury for its time. Whilst the western wall still rises to its original gable height, the battlements and garret that once topped the structure have long since disappeared.

The 18th century brought significant changes to this medieval stronghold, when new owners added a two-storey extension on the western side complete with kilns, suggesting the castle had evolved from defensive fortress to working estate building. The second floor underwent extensive remodelling during this period as well, transforming the interior to suit Georgian tastes whilst preserving the robust medieval shell. Archaeological surveys suggest the island may have been inhabited even before the castle was built, adding another layer to this site’s long history of occupation.