The castle’s name derives from the Irish “Leac Ó bhFionnáin”, meaning “the flagstone of the O’Finnans”, pointing to the family who likely held these lands before the tower was built. The structure itself is a typical example of the tower houses that proliferated across Ireland during this period; sturdy stone fortifications that served as both defensive strongholds and comfortable residences for the landowning classes.

The castle is a rectangular tower measuring approximately 12 by 9 metres, rising to four storeys with an attic level above. Its walls, built from local limestone, are nearly two metres thick at the base, tapering slightly as they rise. The entrance, positioned at ground level on the eastern wall, would originally have been protected by a murder hole above, whilst narrow loop windows on the lower floors provided defensive positions for archers or musketeers. The upper floors, which housed the main living quarters, feature larger windows with stone mullions, indicating a greater emphasis on comfort and light once you climbed beyond the defensive lower levels.

Though now roofless and partially ruined, Lackafinna Castle retains many interesting architectural features. The remains of a spiral staircase can be traced in the north-eastern corner, whilst corbels that once supported timber floors are still visible projecting from the inner walls. A notable feature is the presence of a garderobe, or medieval toilet, built into the thickness of the wall; a luxury that speaks to the relative sophistication of the tower’s original occupants. The castle likely remained inhabited into the 18th century before falling into disuse, and today it stands as a weathered but impressive reminder of Galway’s turbulent medieval past, when such towers dotted the landscape as symbols of power and territorial control.