A souterrain is an artificial underground chamber or tunnel, typically stone-lined, built during the early medieval period and associated with ringforts as a place of storage or refuge. The discovery prompted a reclassification of the site: what had been catalogued from aerial evidence alone was now confirmed as a rath, the Irish term for a ringfort, a class of enclosed farmstead that was the dominant form of rural settlement in Ireland roughly between the fifth and twelfth centuries.

The site itself survives not as a visible earthwork but as a cropmark, a faint outline readable from the air when differential soil moisture causes overlying vegetation to grow unevenly above buried features. That mark describes a circular univallate enclosure, meaning a single-ditched ring, approximately 35 metres in diameter. The wider area carries the placename Lios na gCruach, which preserves the Irish word lios, itself a synonym for a ringfort enclosure, suggesting local memory of the site persisted in language long after any physical trace above ground had disappeared. Patrick Power, writing in 1940, noted that two such lioses in the area had been demolished long since, and this site may be one of them, the ground quietly holding what the landscape no longer shows.