A souterrain is an underground stone-lined passage or chamber, typically associated with early medieval settlement, used variously for storage, refuge, or concealment. This one leaves no visible surface trace whatsoever, which places it in a curious category: a site known almost entirely through memory and word of mouth rather than any physical evidence you could point to.

What makes the tradition more than mere folklore is its connection to an early ecclesiastical enclosure in the same area. Early Christian communities in Ireland frequently built souterrains within or close to their enclosures, and the association here suggests a site of some antiquity, even if nothing remains above ground to confirm it. The enclosure itself carries the reference CO015-04601, indicating it is a recognised archaeological feature in its own right. Whether the souterrain was collapsed, quarried away, or simply never disturbed enough to become visible is not recorded. The tradition survives without the archaeology to back it up in any tangible sense.