What reads at first glance as a simple hollow in the earth is actually the surface trace of a souterrain, an underground stone-lined passage or chamber built in early medieval Ireland, typically used for storage, refuge, or both. These structures were often associated with nearby ringforts, the circular earthen enclosures that served as farmsteads across the Irish countryside from roughly the sixth to the twelfth centuries, and this one is no exception.

The sunken area sits approximately one hundred metres to the north-east of a ringfort at Ahalisky. That spatial relationship is fairly typical; souterrains were frequently constructed just outside or at the edge of a ringfort's enclosure, connected to or positioned near the main settlement but buried beneath the surface where their contents, or their occupants in times of threat, would be out of sight. The fact that the souterrain here is visible only as a depression suggests the underground structure has partially collapsed inward over time, leaving the ground above it to sink gradually into the void below.