What was once an underground stone-lined tunnel has quietly folded under its own weight, leaving behind little more than an elongated dip in the ground, the kind of feature that could easily be mistaken for a drainage channel or an old animal burrow.

Souterrains are underground stone-built passages and chambers, typically associated with early medieval ringforts in Ireland, and thought to have served as places of refuge, cold storage, or concealment. Their relationship with ringforts, the circular earthen enclosures that dot the Irish countryside in their thousands, is well established; it was common to construct a souterrain within the interior of such a fort, often tucked against the enclosing bank. At Abbeystrowry, the souterrain sits in the northwest quadrant of just such a ringfort. McCarthy, writing in 1977, noted the overgrown depression that marks the probable location of a collapsed chamber, which is all that remains visible at the surface.