Its existence is easy to miss entirely, which is perhaps fitting for something built specifically to be concealed. This is a souterrain, an artificially constructed underground passage or chamber built from drystone, a technique using carefully fitted stones without mortar. Souterrains were common features of early medieval Ireland, typically associated with nearby settlements and used for storage, refuge, or both. This one sits within a slightly raised, roughly circular area measuring seventeen metres across, the kind of subtle topographical feature that most walkers would pass without a second glance.

The structure has two openings, one on the north-west side and one on the north-east, both currently blocked by collapsed material. Despite the obstruction, the north-east opening reveals enough to show the quality of what lies beneath: the side-walls of a chamber or passage are visible, carefully built and corbelled slightly inward just below where the roofing lintels would sit. Corbelling, the technique of stepping each course of stone slightly over the one below to create a self-supporting vault, is a mark of considered craft rather than hasty construction. Close to the north-west opening, a short section of walling approximately 1.7 metres long has survived; this may be the remnant of an associated hut, suggesting the souterrain once sat within or beside a small dwelling. Together, the raised platform, the paired openings, and the trace of a building above ground point to a coherent, planned site rather than an isolated curiosity.

Access is not possible at present, both because the openings are blocked and because the site sits on private land on the Iveragh Peninsula. The most a visitor can realistically do is observe the slight rise in the ground and, if conditions allow, peer into the north-east opening to glimpse those corbelled walls. The view from the slope, looking out over the Ferta estuary, gives a reasonable sense of why someone once chose this particular position: sheltered, well-oriented, and commanding a clear line of sight to the water below.