This is a souterrain, an underground passage or chamber built from dry stone, typically associated with early medieval settlement in Ireland and used variously for storage, refuge, or both. What makes this particular example quietly remarkable is precisely its invisibility: nothing above ground gives it away.

The structure was investigated in 1976 by Dr E. Shee-Twohig, and described subsequently by McCarthy in 1977. It consists of a single sub-rectangular chamber, roughly 2.9 metres long, between 0.7 and 0.85 metres wide, and just over a metre and a third in height, oriented on a northwest to southeast axis. The walls are stone-built, and the chamber was roofed with capstones, though one of these had been removed by the time it was recorded. Access was via a stone-built entrance shaft at the southern end of the southwestern side, itself covered by two capstones and leading into the chamber through a lintelled opening. The only find recovered was a single animal bone. The souterrain lies within what is thought to be a ringfort, the circular earthwork enclosure that was the dominant form of rural settlement in early medieval Ireland, typically surrounding a farmstead and its outbuildings. The association between ringforts and souterrains is well established, with underground chambers often constructed to serve the household above.