Dunboy Castle (Irish: Caisleán Dhún Baoi) is a castle on the Beara Peninsula in south-west Ireland near the town of Castletownbere. It was a stronghold of the O’Sullivan Bere, a Gaelic clan leader and ‘Chief of Dunboy’, and was built to guard and defend the harbour of Berehaven. Its presence enabled O’Sullivan Bere to control the sea fisheries off the Irish coast and collect sizeable taxes from Irish and Continental fishing vessels sheltering in the haven. It was also a centre for the import/export trade to and from the Continent. Today, much of the castle is destroyed but the ruins are open to the public.
Dunboy Castle was the scene of the famous Siege of Dunboy in the summer of 1602 which ultimately led to its destruction and the breaking of the power of the O’Sullivan Bere. At that time Donal Cam O’Sullivan Bere was in rebellion against the English crown and Elizabeth I had sent a 5000-strong army under the command of Sir George Carew to suppress the insurgents. Even with its small garrison of 143 men Dunboy Castle was thought to be impregnable but following a fierce artillery bombardment the walls were smashed and after some desperate hand-to-hand fighting amid the rubble the defenders were finally overcome. The 58 survivors of the two-week siege were executed in the nearby market square.
Near the castle ruins stands Puxley Mansion, a 19th-century manor house. It was burnt to the ground by the IRA in 1920 in reprisal for the destruction of houses that harboured IRA men and weapons by the Crown Forces. Plans to refurbish the mansion were halted in 2011.