The field at Kilpatrick in north Cork looks like any other, its surface giving nothing away. But from the air, a ghost emerges: a near-perfect circle roughly fifty metres across, betrayed only by the differential growth of crops over buried soil disturbance. This kind of cropmark, where a filled-in ditch or fosse causes the vegetation above it to grow slightly taller or a different shade in dry summer conditions, is one of the quieter ways that archaeology makes itself known. It requires the right season, the right angle of light, and someone looking down at the right moment.

The enclosure was first recorded in an aerial photograph taken in July 1967, part of the Cambridge University Collection of Aerial Photography. What the photograph captured was the outline of a fosse, the ditch that would originally have ringed a circular enclosure of the kind common across early medieval Ireland. Such enclosures, often called raths or ringforts depending on their construction, served variously as farmsteads, high-status residences, or sites of local significance. The one at Kilpatrick has long since been levelled, ploughed over, and absorbed into the agricultural landscape. A faint linear cropmark also crosses the interior, running just north of centre and continuing into the adjoining field on both sides; this is thought to represent a field boundary, itself now gone, that someone at some point drew straight across the already-forgotten circle beneath their feet.