The one at Kilmalooda in County Cork came to light not through careful excavation but through the less ceremonious process of quarrying, in November 1981, when machinery cut through its outer passage and exposed what lay beneath the surface.

The structure sits within the northern quadrant of an early ecclesiastical enclosure, the kind of roughly circular boundary that would once have marked out a monastic or church settlement in the early Christian centuries. Three chambers had been cut into the gravel, each roughly rectangular and low, the largest no more than 2.7 metres long and 1.2 metres high. By the time the site was recorded, considerable collapse had already occurred across all three chambers. The third chamber retained a distinctive detail: four sandstone slabs set into its southern wall, their original function unrecorded but their careful placement suggesting deliberate construction rather than improvisation. It was the passage leading into this third chamber that the quarry face exposed, which is how the whole complex came to light at all.

The dimensions, all approximate, give a sense of how confined the space would have been: Chamber 2, at just under a metre in height, would have required anyone moving through it to crouch low. Whether used for sheltering people or storing perishables, the souterrain was never meant to be comfortable, only useful. Its position within an ecclesiastical enclosure connects it to a wider pattern seen across Ireland, where early monastic communities incorporated these underground structures into their settlements, their precise purposes still debated by archaeologists.