Running along the inner face of a ringfort's bank, the hollow measures roughly 22.5 metres in length, 5.2 metres wide, and drops about 1.45 metres at its deepest point. The working hypothesis, recorded when the site was inspected in 1976, is that this is the collapsed remains of a souterrain, an underground passage or chamber built during the early medieval period, typically used for storage, refuge, or both. The roof has long since given way, leaving only this elongated scar in the soil as evidence of what once ran beneath.

The souterrain sits in the south-east quadrant of a ringfort, a type of enclosed farmstead common across early medieval Ireland, usually defined by a circular bank and ditch. This particular example occupies a small natural hillock surrounded by low-lying marshy ground, a setting that would have made the elevated enclosure conspicuous and defensible in a landscape prone to flooding. The marshy terrain also helps explain the survival of old field boundaries visible to the south of the ringfort, running roughly east to west, and a deep drain cut north to south to the east. These features hint at a landscape that has been managed and worked for a very long time, with the ringfort itself forming only one layer in a much older pattern of land use.