That cross is not simply a field marker or a pious gesture; locally, it is believed to sit directly above the entrance to a souterrain, an underground passage or chamber of the kind commonly associated with early medieval settlement in Ireland, often used for storage or refuge. The combination is quietly odd: an ancient subterranean feature apparently capped, at some later point, by a modest Christian symbol.

The enclosure itself is modest in scale, roughly fourteen metres in diameter, defined by a low bank of earth and stone no more than sixty centimetres high. Such circular enclosures are a familiar feature of the Cork countryside, frequently the remains of a rath or ringfort, the enclosed farmsteads that once housed early medieval families across Ireland. The bank at Curragh is worn and unassuming, and would be easy to pass without a second glance. What draws the eye, and the curiosity, is that north-eastern section of the bank where the stones are heaped up and the iron cross stands. Whether the cross was placed there as a marker by someone who knew what lay beneath, or as a way of sanctifying or sealing something older, is not recorded. The association between the cross and the suspected souterrain entrance survives only as local tradition, but that tradition has evidently been persistent enough to be noted.