That is all. Beneath it, or beneath what remains, lies a souterrain, an underground stone-built passage or chamber constructed in early medieval Ireland, typically as a place of refuge, storage, or concealment. The structure has been so thoroughly reclaimed by the earth that its full extent can only be inferred from the one exposed stone: the lintel's long axis runs north to south, suggesting the passage itself ran east to west.

The site was significant enough to be marked by name on the third edition of the Ordnance Survey six-inch map, surveyed in 1926 to 1927, which labels it plainly as 'Souterrain', a rare acknowledgement for a feature that by then was already almost entirely invisible. Local tradition also speaks of a fort on the hillock, which would fit a familiar pattern: souterrains are frequently found in association with raths or ringforts, the enclosed farmsteads of early medieval Ireland, and were often built into the interior or banks of those earthworks. Here, however, no trace of any enclosing bank or ditch survives at the surface, leaving the tradition unconfirmed by anything the eye can find.