The site refuses to give a definitive answer. A souterrain is an underground stone-built passage or chamber, typically associated with early medieval settlement, used for storage, refuge, or both. What survives here, if the identification is correct, is the roof's absence: a sunken trace in the earth where the structure has caved in, leaving only its outline.

The depression sits within a ringfort, the circular enclosure of raised earthen banks that served as a farmstead and home for a family of some local standing during the early medieval period, roughly from the fifth to the twelfth century. Souterrains are frequently found within ringforts across Ireland, often positioned near the interior of the enclosing bank or at the heart of the enclosed space, as appears to be the case here. D. Lavelle's 1994 archaeological survey of the Ballinrobe district, which encompasses the areas around Lough Mask and Lough Carra, recorded the feature but noted it was inaccessible at the time, meaning its true nature could not be confirmed. The careful hedging in that record, a depression that "may be" a collapsed souterrain, is itself revealing: the site is ambiguous enough that certainty was impossible, yet distinctive enough that the identification remained plausible.