The only way it has ever been seen is from the air, and even then only under the right conditions, when growing crops betray what the soil conceals. This is a ring-ditch, the buried remnant of a circular enclosure whose fosse, the defining ditch that once outlined the structure, survives as a ghost in the earth roughly seven metres across.

Ring-ditches are generally understood to be the eroded traces of prehistoric funerary or ceremonial monuments, often the last remnants of round barrows whose earthen mounds were long ago levelled by centuries of ploughing. They appear on aerial photographs as cropmarks, a phenomenon that occurs when buried ditches retain more moisture than the surrounding subsoil, causing the crops directly above them to grow slightly taller or ripen at a different rate, producing a faint but readable discolouration visible from altitude. The Blanchvillestown example was identified precisely this way, captured in aerial photographs taken on 22 July 2000. What makes the site particularly interesting is that it does not stand alone. Two further ring-ditches lie within roughly 26 metres and 40 metres to the north-north-west, suggesting this corner of Kilkenny was once a focus of repeated or clustered activity, the kind of landscape pattern that often points to a prehistoric burial ground used across generations.