The enclosure at Warrington, in County Kilkenny, offers none of that. It exists, as far as anyone can tell from the ground, not at all. What betrayed it was a dry summer and a camera mounted in a low-flying aircraft: on 16 July 1971, an aerial photograph captured the ghostly outline of a sub-rectangular enclosure pressed into the cropmarks of a field, the differential growth of plants above buried features drawing a shape that centuries of ploughing and pasture had otherwise erased.

Cropmark archaeology works because buried ditches or banks, even when levelled to nothing visible above ground, alter the soil in ways that affect how crops grow above them. In a dry season, those differences become legible from the air as darker or lighter stripes and patches. The Warrington enclosure, recorded on a photograph from the Cambridge University Collection of Aerial Photography, measures at minimum roughly 130 metres east to west and around 40 metres north to south. It sits in close relationship with a second, adjacent enclosure to the south-east, extending some 20 to 30 metres westward from the northern portion of that neighbour, with its northern side running east to west approximately 30 metres further north. The two features appear to form part of a larger, interconnected complex, though the sub-rectangular enclosure seems to continue beyond a field boundary to the east, where no cropmark trace is visible, leaving its full extent unknown.