Dunboy Castle, Medieval fortress in West Cork, Ireland

Dunboy Castle is a medieval fortress on a coastal promontory near Castletownbere in West Cork. Stone walls stretch across the site overlooking the harbor and the Atlantic Ocean.

The O'Sullivan Bere clan built Dunboy Castle in the 15th century to guard Berehaven harbour, control sea fisheries and tax Irish and continental fishing vessels sheltering there. In summer 1602, during the Nine Years' War, Sir George Carew's 5,000-strong army battered down the walls with artillery; the 143-man garrison was overcome in hand-to-hand fighting and the 58 survivors were executed in the nearby market square.

The castle's Irish name, Caisleán Dhún Baoi, is still used locally and appears on signage. The 58 survivors of the 1602 siege were executed in the market square of Castletownbere, and the site is remembered in the town's lore. Visitors today see only ruined walls and a grassy terrace, with no inscriptions on the masonry.

The ruins are accessible through the surrounding estate, though visitors should wear sturdy footwear due to uneven ground and partial stone structures. Be prepared for exposed coastal conditions with wind and changing weather.

The 143-man garrison surrendered after a two-week siege, and the 58 survivors were executed in the market square of Castletownbere. The castle's ruins and the 17th-century bastion fort built on the site were surveyed by arachnologist Edward M. Fahy in the late 1960s.