The depression, running roughly nine and a half metres from the centre of an adjacent rath out towards its edge, is narrow, between one and one point eight metres wide, and sinks no more than forty centimetres below the surrounding ground. The interpretation is cautious but specific: this could be a collapsed souterrain, an underground passage or chamber typically built during the early medieval period, usually of dry-stone construction, and associated with the ringforts known as raths. Souterrains were used variously for storage, refuge, or concealment, and their presence within or near a rath is well attested across Ireland.

The rath itself sits to the south of the feature, and together they occupy a position that would have commanded a clear view down the length of the Glenade valley, which runs on a northwest to southeast axis through this part of Leitrim. Whether the souterrain, if that is what it is, ever served its intended purpose or was abandoned before completion is unknown. What remains is a long, faint scar in the slope, most legible as an anomaly in the ground rather than as any obvious structure.