Where the buried ditch of a fosse, a defensive trench dug around a settlement, interrupts the soil, the crop above grows differently, and that faint difference in growth patterns is enough to betray the presence of something far older. The shape it traces is unusual: not the familiar circle of the typical ringfort but a subtriangular form, sometimes described as plectrum-shaped, roughly 43 metres north to south and 40 metres east to west, narrowing towards the north. It was identified and reported by Jean-Charles Caillère, working from satellite imagery.

The significance of that unusual shape becomes clearer when it is set alongside comparable sites. An excavated enclosure of almost identical form at Newtown, Co. Limerick was found to date from the early medieval period, specifically the 7th to 10th centuries A.D., and was classified as a ringfort on the basis of that evidence. A similarly shaped enclosure at Islandduane, also in Co. Limerick, has been placed in the same category. Ringforts, the most common field monument type in Ireland, were typically circular earthen enclosures used as farmsteads during the early medieval period, and they appear in their thousands across the country. The subtriangular variant is considerably rarer, which makes the Kilkenny example, still unexcavated and known only through cropmark evidence, a quietly anomalous presence in a ploughed field. Its position is recorded immediately to the north-east of a trigonometrical station marked on the first edition Ordnance Survey six-inch map, itself a useful anchor point in the landscape.