The structure is a souterrain, an underground passage or chamber built in dry-stone walling and used in early medieval Ireland typically for storage, refuge, or both. What makes this one quietly arresting is not what has been found inside it, but what has not. At its western end, a low opening barely five centimetres high and forty centimetres wide extends into the darkness for at least two metres, leading, most likely, to a further chamber or passage. Standing water and accumulated fill have made it impossible to investigate further.

The accessible portion is compact but carefully constructed. A vertical entrance shaft at the eastern end, covered by two loose stones and roughly sixty-five centimetres across, drops 1.3 metres before opening at floor level into the main chamber. That chamber, aligned east-northeast to west-southwest, is roofed by four flat slabs laid across slightly inclined dry-stone walls, and measures 1.6 metres long, 0.9 metres wide, and 1.3 metres high. Near the western end, a large slab projects inward just below the roof line, spanning the full width of the wall; below it sits that tantalisingly narrow gap leading further west. The structure was first described in J. Cuppage's 1986 archaeological survey of the Dingle Peninsula, Corca Dhuibhne, by which point it had been known for only around five years, having lain concealed beneath its stone mound until somebody began clearing the hillside.

The hill itself rises to 254 metres and the souterrain sits on its northern face, looking out over the Lispole valley. What lies beyond that low western opening remains, for now, a matter of reasonable conjecture rather than confirmed fact. The water level alone has so far decided the question.