A rubble-filled depression, roughly 3.6 metres across and less than a metre deep, sits about ten metres from the western edge of the site. On its north-western side, three large flat slabs protrude in a way that suggests the entrance to a souterrain, an underground passage or chamber built during the early medieval period, typically used for storage, refuge, or both. The opening is blocked, the depression filled with loose stone, and whatever lies beyond those lintels remains, for now, inaccessible.

Souterrains are found across Ireland in considerable numbers, often associated with early Christian settlements or ringforts. They were generally constructed from dry-laid stone, roofed with large capstones or lintels, and built just below ground level. The name of this townland, Inse Fhearann Na Gcléireach, carries a Gaelic reference to clerics or churchmen, hinting at ecclesiastical activity in the area, which would be consistent with the kind of early medieval settlement that typically produced souterrains. The three visible lintels at the north-western edge of the depression indicate that the passage, if intact, runs in that direction beneath the ground. The site was recorded as part of the archaeological survey of the Iveragh Peninsula compiled by A. O'Sullivan and J. Sheehan, published by Cork University Press in 1996.