Dunboy Castle is a broken coastal ruin west of Castletownbere, near the mouth of Bearhaven harbour. It does not look like much at first glance: low walls, grass, sea air, and the sombre bulk of Puxley Mansion nearby. The history carries the place.
This was the O'Sullivan Bere stronghold, destroyed by English forces in 1602. Come for the setting and the story rather than architecture. The short detour pairs well with the shoreline around Dunboy and a look at the fenced-off shell of Puxley Mansion.