A souterrain, the term for an underground stone-lined tunnel or chamber built in early medieval Ireland, typically for storage or refuge, once lay on the southern side of an early ecclesiastical enclosure here. There is nothing to see at ground level now, no depression, no exposed stonework, no sign that anything was ever disturbed. Its existence is known only through older records and the memory of description.

What those descriptions preserve is modest but telling. The Ordnance Survey Name Books, compiled in the nineteenth century as part of a systematic effort to record placenames and local antiquities across Ireland, noted that the souterrain was roughly constructed, with stones forming the sides and large flat flags laid across the top to make a roof. Hartnett, writing in 1939, passed this account along, and it remains the closest thing to a physical description the site has. The enclosure it belonged to is early ecclesiastical in character, meaning the souterrain was likely associated with a monastic or church settlement of the early medieval period, when such underground structures were commonly built in proximity to religious sites as well as farmsteads. Whether it was used for cool storage, as a place of concealment during raids, or for some other purpose is not recorded.