That inaccessibility is, in its own way, the most interesting thing about it.

The historian William Carrigan, writing in 1905 in his four-volume history of the diocese of Ossory, noted the presence of what he called a "cave or underground chamber" lying beneath the house platforms within the ringwork, a type of earthwork enclosure defined by a circular or oval bank and ditch rather than the raised internal mound associated with a motte. He placed the entrance on the eastern side of the site's interior. The structure he was describing is almost certainly a souterrain, an underground passage or chamber built from stone or cut into the earth, typically associated with early medieval settlement in Ireland. Souterrains served various purposes depending on the site; cold storage, refuge, and access between enclosed spaces have all been proposed by archaeologists. Whether this example was constructed as part of the ringwork's original layout or predates it is not recorded. Carrigan's brief notice is the only historical account of the chamber, and it has apparently remained sealed or obscured since at least that time.