Before revision: Donaghmore Souterrain, discovered in County Louth in 1960, and Drumlohan Souterrain , County Waterford are the only souterrains to be an Irish National Monument.
After revision: Donaghmore Souterrainin discovered in County Louth in 1960, and Drumlohan Souterrain , County Waterford are the only souterrains to be an Irish National Monument.