A souterrain is an underground stone-lined passage or chamber, typically constructed during the early medieval period and associated with ringforts, those circular enclosures of raised earthen banks that dot the Irish countryside. They served variously as storage spaces, refuges, or escape routes. The one recorded here leaves the question of its own existence genuinely open.

In 1934, a researcher named Bowman described a curious feature on the north-west side of the ringfort: the rampart curves inwards to form a roughly circular enclosure, some eighteen feet in diameter and around six feet deep, with an opening about six feet wide leading from the fosse, the defensive ditch surrounding the fort. Bowman concluded this was a souterrain. What complicates matters is that the 1842 Ordnance Survey six-inch map, one of the most detailed early cartographic records of rural Ireland, appears to show a lime kiln, a simple stone structure used to burn limestone into agricultural quicklime, in the north-east bank of the same ringfort. It is possible that what Bowman interpreted as a souterrain entrance was in fact the remains of that kiln, a utilitarian feature easily confused with something older and more deliberate when much of the structure has collapsed or been absorbed back into the earthworks. There is no visible surface trace of anything today. A second souterrain is also recorded within the same fort, which suggests the site was once genuinely complex, even if its details are now largely invisible.