Built directly on bedrock from random rubble and lime mortar, this 15th or 16th century tower house now reaches only about six metres at its highest point; a shadow of its former glory after Parliamentary forces razed it in 1652. The castle’s name sometimes appears as Poolcastle in historical records, and despite its ruinous state, the remains still tell a fascinating story of medieval Irish architecture.

The surviving structure consists of two conjoined rectangular blocks that reveal sophisticated medieval planning. The eastern block, measuring roughly 8.9 by 7.3 metres, contains a small chamber with intriguing features in its northern wall: two vertical shafts that once served as garderobes for the upper floors, with an arched opening on the exterior that likely connected to this medieval plumbing system. The larger western block, though partially modified in the 19th century when someone attempted to create a viewing platform, preserves evidence of at least two vaulted chambers. These rooms, once covered by wicker-centred vaults that have since collapsed, would have provided living and storage spaces typical of a tower house of this period.

Today, visitors crossing the causeway to this 50 by 20 metre island will find a romantic ruin that speaks to centuries of Irish history. From its construction by the Mac Carthy More dynasty, one of Munster’s most powerful Gaelic families, through its destruction during the Cromwellian conquest, to its Victorian afterlife as a picturesque viewpoint, Castlelough Castle embodies the layers of history that characterise so many Irish monuments. The fragmentary walls, some extending well beyond their current ruins, hint at what must have been an impressive defensive residence commanding views across Lough Leane.