Some archaeological sites announce themselves with tumbled walls or a hollow in the ground. This one in Parkbeg, County Waterford, offers nothing so obliging. A circular enclosure of roughly fifty metres in diameter, it sits on a slight ridge in low-lying pasture with a pond nearby, and leaves no impression whatsoever on the surface. Stand where it should be and you would have no reason to suspect anything was there at all.

The site was first recorded as a faint mark on the 1840 edition of the Ordnance Survey six-inch map, the great nineteenth-century mapping project that captured Ireland's landscape in unprecedented detail. Even then, the notation was tentative. The enclosure may not be an independent feature at all; one possibility is that the cartographers misread or displaced a nearby ringfort, a type of enclosed farmstead typically dating to the early medieval period, which lies immediately to the north-west. If that is the case, then what appears on the map as two separate features may in fact be a single site recorded twice, once accurately and once with the coordinates slightly off. It is a reminder that historical maps, however careful, were made by people working in difficult conditions across unfamiliar terrain, and that an entry on a map can sometimes tell you more about the limits of surveying than about what lies beneath the ground.