The original lintelled entrance, the kind of low, carefully roofed opening typical of these underground chambers, has been blocked, and the only way to glimpse what lies beyond is through a small accidental hole in the masonry, a gap that was never meant to be there.

Souterrains are stone-built underground passages or chambers, constructed during the early medieval period and found across Ireland, generally thought to have served as places of refuge, cool storage, or concealment. What makes this particular example unusual is its location, not cut into the earth in the conventional way, but hollowed into the fabric of a clochaun, a corbelled stone beehive hut of the kind associated with early Christian and early medieval settlement along this Atlantic fringe. The passage, according to the survey of the Corca Dhuibhne area compiled by J. Cuppage and published in 1986, is roughly 1.75 metres wide and at least 2 metres long. That minimum length suggests the full extent of the chamber may never have been properly assessed, the blocked entrance having prevented any thorough investigation.