A souterrain is an underground stone-lined passage or chamber, typically associated with early medieval settlement in Ireland, used variously for storage, refuge, or ventilation of nearby structures. This one announced itself unexpectedly in 1986, when the ground collapsed during road construction on a north-east-facing slope, briefly revealing an opening before it was closed off and the road was built straight over it.

The circumstances of the discovery are as accidental as they come. No excavation preceded it, no formal investigation followed, and what survives is essentially a piece of local memory: the ground gave way, something was glimpsed, and then it was sealed again. The qualifier "possible" attached to its status reflects this. Without excavation or survey, the chamber cannot be confirmed as a genuine souterrain, though the manner of the collapse, a sudden subsidence into a void, is consistent with how such underground structures tend to make themselves known. The road leading south-west to a nearby house now passes directly over whatever lies beneath.

There is nothing to see at ground level. The site is notable precisely because it is invisible, a piece of potential archaeology folded back into the landscape by the same construction work that uncovered it. It is the kind of place that rewards thinking about rather than visiting.