When a roof lintel shifted during routine tillage, it opened a gap into a souterrain, an artificial underground passage or chamber built in early medieval Ireland, typically associated with a nearby ringfort and used for cold storage, refuge, or both. What emerged from the disturbed earth was an oval, stone-lined room that had sat undisturbed, and very nearly unnoticed, for perhaps a thousand years.

The chamber itself is compact but carefully made. Measuring four metres north to south and only 1.3 metres east to west, with a height of just over a metre, it would have required a person to crouch or crawl to use it. The walls are of dry rubble construction and lean inward as they rise, a technique that helps the structure support the weight of the lintelled roof above. In the north-east corner, at 0.8 metres above the floor, a small lintelled opening, only 0.4 metres wide and 0.3 metres high, connects to what is thought to be the original entrance passage, which extends at least three metres further. The souterrain sits in the north-east quadrant of a rath, the circular earthwork enclosure associated with an early medieval farmstead, which still survives nearby. The tight, awkward dimensions of that entrance opening are characteristic of the type; an intruder would have been slowed considerably trying to squeeze through it, and that was very likely the point.