Castle Donovan stood amid the rugged grandeur of Mullach Meíse, Doirín-a-Críonaigh and Gleannacloiche in Drimoleague, County Cork. It was the principal seat of the O'Donovan Clan and is now in ruin.
Castle Donovan was built in the year 1560 by Donal O'Donovan or Dónall na gcroiceann, so called because when he was a young child his mother had to wrap him in skins to conceal him from his enemies.
The castle is 47' long, 26' wide and 61' high. The walls are 6' thick .On the top is a very well defined parapet. The Castle was divided into various chambers or rooms. One room was set aside in the old days for food for the garrison and another store room for gunpowder and shot. It is built on a very solid rocky foundation and faces south of the valley. The main door was of heavy oak and was situated in the western-side.