The one at Ballyconra, in the floor of the Nore river valley in County Kilkenny, breaks that pattern entirely. It sits in flat, marshy grassland beside a stream, in terrain that tends to swallow rather than preserve such features, and it was only confirmed to exist when an aerial photograph, taken in 1969 as part of the Cambridge University Collection of Aerial Photography, caught the crop or soil marks that ground level obscures.

What the photograph revealed is a rectangular enclosure, roughly 65 metres along its north-west to south-east axis and around 48 metres across, defined by a slight bank with an external fosse. A fosse is simply a ditch, typically dug to accompany a raised earthen bank, together forming the boundary of a settlement, field system, or enclosure of some kind. What makes the site a little more intriguing is the remnant of an embanked trackway running north-east to south-west at its southern end, suggesting the enclosure was once deliberately approached or connected to something beyond it. The precise date and function of the enclosure remain unassigned; the marshy, low-lying setting beside a river might point toward agricultural or pastoral use, but valley-floor enclosures in Ireland can also reflect early medieval activity associated with watercourses and wetland management. Without excavation, that question stays open.