That passage is a souterrain, a type of drystone-built underground tunnel associated with early Irish settlement sites, most likely used for storage or as a place of refuge. The fact that it exists at all here is mostly a matter of accident: a roofing slab was removed at some point, exposing a short section of the passage, roughly 0.66 metres wide, running in a roughly north to south direction, possibly turning westward at its northern end, though that detail cannot be confirmed.

The cashel sits at about 18 metres above sea level, approximately 200 metres from Caher Point, and within its grass-covered interior there are traces of at least two huts, with a third possible structure visible as a disturbed spread of stones to the south-east of the enclosure's centre. That third spread may equally represent clearance debris rather than the footprint of a building, which is precisely the kind of ambiguity that early medieval settlement sites tend to leave behind. The site was recorded and described by J. Cuppage in the 1986 Dingle Peninsula archaeological survey, a volume covering the Corca Dhuibhne region that remains a foundational reference for the archaeology of this part of Kerry. What the survey captured is a site that had already experienced considerable disturbance, the collapse of hut walls now grass-grown, the souterrain partially open but effectively sealed by its own accumulated infill.

The enclosure is a protected national monument under a preservation order dating from 1984. The souterrain itself is inaccessible, and the surface features are subtle enough that without some prior knowledge of what to look for, the whole site reads as little more than a lumpy field on a modest rise above the bay.