A souterrain is an underground passage or chamber built in early medieval Ireland, typically from drystone construction, and used for storage, refuge, or both. This one is built to that same dry-laid tradition, its stones placed without mortar, and it survives in two distinct chambers where once there may have been a continuous underground run.

The first chamber measures four metres in length and just over a metre and a half wide, oriented east to west, with access currently possible at its eastern end. A section of collapse separates it from the second chamber, which lies to the west and runs north to south, the dimensions here more generous at seven and a half metres long and just under two metres wide. Entry to this second chamber is gained through a breach in its northern side rather than any original opening. At the south-western end, collapsed material hints at what may have been a creep, a low, narrowed passage between chambers that required a person to crawl through, a feature thought to have served a defensive function, slowing down anyone attempting to force entry. The rath above ground, a circular earthen enclosure of the kind common across early medieval Ireland, would have been the farmstead to which this whole arrangement belonged, the souterrain tucked beneath it as a kind of concealed cellar or bolt-hole.