It has never been marked on any Ordnance Survey historic map. It leaves no trace above ground. What it does leave, under the right conditions, is a large oval shadow pressed into the grass, the outline of a structure that has not been seen from the ground in a very long time.

The enclosure at Killeagh came to official attention in September 2002, when the Archaeological Survey of Ireland captured it during low-altitude oblique aerial photography. What the camera recorded, catalogued as ASIAP 309 (13 & 14), was a substantial suboval-shaped cropmark, a phenomenon that occurs when buried features affect how plants grow above them, producing differences in colour or height that are invisible at ground level but legible from the air. The shape measured roughly 43 metres east-northeast to west-southwest and 32 metres north-northwest to south-southeast. A second enclosure, a separate monument, sits about 145 metres to the northwest, suggesting this part of Killeagh preserves traces of a more complex pattern of early settlement or land use. The cropmark reappeared on Ordnance Survey orthoimagery taken between 2005 and 2012, confirming it was not a photographic accident. It had vanished again by the time Digital Globe photographed the area between 2011 and 2013, and was absent once more from a Google Earth image taken in June 2018. The record was compiled by Alison McQueen and Vera Rahilly and uploaded to the Archaeological Survey of Ireland database in September 2020.

There is nothing to see here in the conventional sense, and that is precisely the point. The site sits in low-lying, wet pasture, the kind of land that discourages casual exploration and keeps its archaeology locked beneath saturated soil. No marker indicates the enclosure's location, and without access to the aerial photographs held by the Archaeological Survey of Ireland, a visitor walking across this field would have no way of knowing anything lay beneath their feet. The monument's intermittent visibility in aerial and satellite imagery is a reminder of how much of Ireland's early landscape survives only as a conditional presence, readable in one dry summer, invisible in the next, waiting for the right season and the right angle of light.