The ring-ditch at Borris Big exists only as a faint circular shadow in the soil, roughly ten metres across, defined by a fosse, a shallow ditch that once marked out a boundary or enclosed a burial. It surfaces not to the naked eye but to the camera lens of an aircraft, caught in a single aerial photograph taken on 16 July 1971 as part of the Cambridge University Collection of Aerial Photography. In the summer heat, when crops grow unevenly over disturbed or different soil, the outlines of long-buried features can emerge as distinct bands of colour or stunted growth, a phenomenon known as a cropmark. That July morning, the ring-ditch briefly announced itself to the sky.

The site sits on the flat, low-lying floor of the Nore valley, in land that has since been reclaimed for pasture and tillage, roughly 450 metres east of the river. Ring-ditches of this kind are generally understood to be the buried remnants of prehistoric funerary or ceremonial monuments, sometimes the eroded traces of a round barrow whose earthen mound has been ploughed flat over centuries. What makes the Borris Big example particularly interesting is its proximity to a second monument: a circular enclosure lies approximately 50 metres to the south-east. Whether the two features are related in date or function is not known, but their nearness to one another, on the same stretch of valley floor, is unlikely to be accidental. Clusters of this kind are not unusual in Irish archaeology; significant places tended to attract repeated use across generations.