The depression measures roughly five metres north to south and two metres east to west, and local knowledge identifies it as the mouth of a souterrain, the term for an artificially constructed underground chamber or tunnel typically associated with early medieval ringforts in Ireland. These structures served various purposes, among them storage, refuge, and ventilation for dwellings above ground. What makes this one quietly arresting is not what remains visible but what no longer is.

Within living memory, at least within the landowner's father's generation, the souterrain could still be entered through what was described as a gate. That access point has since collapsed, sealing the passage off from the surface and leaving only the hollow as evidence of what lies beneath. Ringforts, the circular earthwork enclosures within which this souterrain sits, were the dominant form of rural settlement in early medieval Ireland, and souterrains are found within them with some regularity across the country. The combination here, a ringfort with a now-inaccessible underground feature, is not unique, but the detail of the collapsed gate carries a particular kind of domestic weight. Someone's father went down there. Now no one can.