Dunboy Castle is a ruined 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 taxes from Irish and continental European 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 noted 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.
Coordinates 51°37'59.776" N -9°55'28.758" E