Nobody has confirmed this in any formal sense, because the entrance is buried under a tangle of briars, ferns, and bushes too dense to penetrate. The structure in question is a souterrain, a type of man-made underground tunnel or chamber typically associated with early medieval settlement in Ireland, often built for storage, refuge, or ventilation near a ringfort. That one exists here is known only by word of mouth, which gives the site an unusually provisional quality; officially noted, archaeologically unexamined, and physically unreachable.

The passage is said to run northward from its entrance near the southern edge of the ridge, which places it in a fairly typical orientation for such features. Souterrains in County Cork are not uncommon, but many remain unexcavated or inaccessible, and this one sits at the more elusive end of that spectrum. Its association with the landscape around Garranes Lake adds some context: the area carries traces of earlier occupation, and a souterrain in this location would fit a pattern of early medieval land use across the region. Beyond that, the record offers little. No excavation, no measurements, no confirmed date of construction.