This 16th-century tower house was built by the O’Malley family, who controlled much of the western coastline and its waters during the medieval period. The castle’s strategic position allowed the O’Malleys to monitor boat traffic on the lough whilst maintaining their grip on the surrounding territories.

The four-storey limestone structure follows the typical design of Irish tower houses, with thick walls, narrow windows, and a single entrance at ground level that could be easily defended. Inside, a spiral staircase connects the floors, leading to what would have been the main hall and private chambers above. The castle’s most famous association is with Grace O’Malley, the legendary pirate queen who inherited her family’s maritime empire and commanded a fleet of ships from various strongholds along the Mayo coast, though this particular castle was more likely used by other branches of the O’Malley clan.

Today, the castle ruins stand as a monument to the complex political landscape of Gaelic Ireland, when powerful families like the O’Malleys operated as semi-autonomous rulers, collecting taxes from fishing vessels, trading with continental Europe, and occasionally engaging in piracy. The site remains freely accessible to visitors, who can explore the ground floor and imagine the castle in its heyday, when it served as both a family home and a symbol of O’Malley power over land and sea.