Castle, Castlereagh sits quietly near the village of the same name, its weathered stones bearing witness to centuries of change in this western corner of Ireland. The structure itself is a tower house, a type of fortified residence that became popular amongst the Irish gentry during the late medieval period when security concerns demanded both comfort and defence.

Built sometime in the 15th or 16th century, the castle likely belonged to a local Gaelic family or perhaps one of the Norman families who had, by that time, become “more Irish than the Irish themselves”. These tower houses served as both symbols of status and practical strongholds, featuring thick walls, narrow windows, and multiple floors that could house extended families, servants, and supplies. The ground floor typically stored goods and livestock, whilst the upper levels contained living quarters and a great hall for entertaining; a clever arrangement that maximised both space and security.

Today, Castle, Castlereagh stands as a reminder of a time when the Irish landscape was dotted with hundreds of such structures, each controlling its own small territory. Many tower houses fell into ruin following the Cromwellian conquest of the 1650s, when new laws prevented Catholics from owning fortified dwellings. Those that survived often did so by being incorporated into later manor houses or by simple neglect, left to slowly crumble as Ireland’s political landscape shifted around them. This particular castle, whilst not as famous as some of Mayo’s grander ruins, offers visitors a genuine glimpse into how minor nobility once lived, defended their lands, and navigated the complex world of Gaelic and Anglo-Irish politics.