Look more carefully, though, and it may be something considerably older and more politically charged: a surviving fragment of the Pale Ditch, the boundary that once marked the limits of English colonial control in medieval Ireland.

The Pale, broadly speaking, was the area around Dublin within which English law and administration held sway during the later medieval period. Its frontier was marked in places by a physical earthwork, a ditch and bank combination intended less as a military fortification and more as a legal and administrative boundary, a line separating the governed from the ungoverned. The section at Kilgobbin, along the southern boundary of Greenfield House, was identified as a possible stretch of this feature by Goodbody in 1993. It runs on a roughly east to west axis along a north-east facing slope, a hillside that drops away to a river some eight metres below the surrounding ground level. The earthwork itself consists of a roughly continuous linear bank of earth and stone, standing about one metre high, just under a metre wide at the top and around one and a half metres at the base. The associated ditch sits on the southern, uphill side of the bank and measures approximately 1.8 metres across. It is most clearly visible at the western end, where the ground conditions have preserved the feature better.

Access to this site requires some patience. The earthwork sits along the boundary of private property at Greenfield House, and heavy vegetation now obscures much of what survives. Any visit should account for this; the bank and ditch are far easier to read in late autumn or winter, when leaf cover thins and the underlying topography becomes legible again. The western end of the feature, where the ditch is most pronounced, is the better place to orient yourself if you are trying to trace the line of the earthwork. Given its tentative identification, it rewards a measured kind of attention, one that holds the question open rather than expecting a clean answer.