A four-storey O'Donovan tower house of 1560 on a rocky crag above the River Ilen, its south-west corner blasted away by Cromwellian gunpowder and left as a free, unguided ruin.
Look for the machicolated doorway, the stone box over the entrance that let defenders drop stones on anyone at the door, and the overhanging corner turrets (bartizans) at the north-east and south-west. Inside, the original spiral stair still winds up the corner.
Castledonovan is a typical four-storey Irish tower house, built around 1560 by Dónall na gcroiceann O'Donovan and the principal seat of the clan. It is a National Monument in state guardianship, freely accessible but unguided, and only a small entrance hallway is open.
A whole corner of the tower is missing. Cromwellian soldiers packed explosives against the base in the 1640s and blew out the south-west angle, and that gouge is still the first thing you notice coming up the road.
Signed walking routes of roughly 3.5 to 9 km cross the valley and upland farmland around Drimoleague, and the castle car park makes a natural start. Dogs are welcome on leads.
Come early or late. Low sun off the east side catches the stone, and the ruin photographs far better than under flat midday light, with the rugged hills of Mullach Meíse and Gleannacloiche behind it.
The ruin itself is a twenty-minute look. Drimoleague is about 6 km south, Skibbereen roughly 15 minutes beyond that, with its heritage centre and market-town lunch stops.
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