When workers were laying the Cork to Dublin gas pipeline in the early 1980s, they uncovered a souterrain, an underground stone-built passage and chamber system of early medieval Irish origin, typically associated with nearby settlement and used for storage or refuge. The structure had sat undisturbed on the summit of a hill in undulating terrain, its existence entirely unknown until the pipeline cut through.

The souterrain, recorded by archaeologist M. F. Hurley in 1987, ran sixteen metres from east to west and comprised three sub-rectangular chambers connected by narrow creepways, the low crawl-passages linking one chamber to the next. The chambers varied in height, two of them rising to around 1.8 metres while the first was a notably cramped 0.6 metres. All three were constructed of dry-stone limestone walling, corbelled inward at the top and sealed with large capstones, a building technique requiring considerable skill and no mortar. Two separate entrances, one facing north and one east, converged into a single passage just 0.7 metres wide. As significant as the structure itself was what it implied about the surrounding landscape: the souterrain lay within the western half of a ringfort, a type of enclosed early medieval farmstead defined by earthen banks or stone walls, that had been so thoroughly levelled over the centuries it had never previously been recorded. The excavation yielded a polished bone point, part of a bronze ringed-pin, and a small quantity of animal bones, modest finds, but ones consistent with domestic activity on an inhabited farmstead.