Barely enough to crawl through, it measures just 82 centimetres wide and 55 centimetres high, and its walls are a mix of careful drystone work and packed earth. This is a souterrain, an underground chamber or passage built during the early medieval period, most likely used for storage or as a place of refuge. What makes this one quietly remarkable is its setting: it sits inside a cashel called Cathair Deargáin, a roughly circular stone enclosure on a west-northwest-facing slope, surrounded by five well-preserved clocháns, the corbelled beehive huts that characterise early Christian settlement on this peninsula.

The cashel itself is a protected National Monument, and the five clocháns within it are in unusually good condition. The souterrain described here enters through a well at the base of the western wall of one of those huts, then branches in opposite directions: 2.2 metres running west beneath the hut wall, and a further metre running east under the floor itself. There may be a second souterrain elsewhere within the enclosure, though the evidence for it is less certain. The site sits on a slope with wide views across the northern side of the Dingle Peninsula, a position that would have made it both agriculturally useful and easy to watch over. J. Cuppage documented the site in the 1986 Corca Dhuibhne archaeological survey, which remains one of the most thorough investigations of early settlement on this part of the Kerry coast.