That uncertainty is, in its own way, the most interesting thing about it. A circular earthwork, the kind of low-profile enclosure that appears throughout the Irish landscape in various forms, was spotted from the air in the summer of 1968, recorded, and has since effectively vanished, at least as far as any ground-level evidence is concerned.

The site came to attention through an oblique aerial photograph taken on 20 July 1968 as part of the Cambridge University Collection of Aerial Photography, reference CUCAP AVT028. Aerial photography of this kind, carried out systematically from the mid-twentieth century onwards, has been responsible for identifying enormous numbers of Irish monuments that left no obvious trace at ground level, their outlines betrayed instead by subtle variations in crop growth or soil colour visible only from altitude. The earthwork in question sits approximately 170 metres southwest of a known ringfort, the kind of circular enclosed settlement used across Ireland from the early medieval period roughly between 500 and 1000 AD. Its proximity to that ringfort is suggestive, though no firm relationship between the two has been established. Significantly, the circular feature does not appear on any historic Ordnance Survey Ireland maps, meaning it was either already levelled or simply too faint to register by the time systematic mapping was underway. Later orthophotography taken between 2005 and 2012, as well as Google Earth imagery, shows no surface remains. A further aerial photograph was taken by the Archaeological Survey of Ireland on 13 September 2002, reference ASIAP 303/21, confirming continued interest in the location without resolving what, precisely, lies there. The record was compiled by Martin Fitzpatrick and uploaded in June 2021.

For anyone inclined to visit, the site is in pasture land in Knocklong West, and there is nothing to see on the ground in any conventional sense. The value here is conceptual rather than visual: a place defined almost entirely by a single photograph taken over half a century ago, showing a shape that the earth has since declined to confirm or deny. Those interested in how Ireland's archaeological record is assembled, layer by layer and image by image, will find the story of this site a useful illustration of how tentatively some monuments are held.