A souterrain, to use the technical term, is an artificially constructed underground passage or chamber, typically associated with early medieval ringforts in Ireland and thought to have served for storage, refuge, or both. This particular example is invisible to any visitor who might stand directly above it.

The chamber was recorded by Coleman in 1947, who found a rectangular, earth-cut room measuring roughly two metres long, just over a metre wide, and about a metre and a quarter high, with a barrel-vaulted ceiling formed by the curve of the earthen roof. Its long axis runs northeast to southwest, and at the northeast end the structure had already collapsed by the time of Coleman's investigation, blocking any further exploration in that direction. At the opposite end, a narrow passage or vent extends for approximately three-quarters of a metre, though whether this was an intentional ventilation shaft or simply an animal burrow had not been resolved. The souterrain lies within the southwest quadrant of the associated ringfort, a circular earthwork enclosure of the kind that served as a defended farmstead in early medieval Ireland, probably between the sixth and tenth centuries.

The southwest quadrant of the ringfort was described as heavily overgrown, with no visible surface trace of the souterrain remaining. The site does not announce itself.