No earthwork rises from the grass, no ditch breaks the surface, no stone marks a boundary. The only evidence that something once occupied this patch of level pasture comes from a single aerial photograph taken on 16 April 1974, in which a sub-circular form approximately 30 metres in diameter became briefly legible from the air in ways that centuries of ground-level observation had never revealed.

The photograph, catalogued as GSI S.650/49, was taken as part of a geological survey flight and shows a cropmark or soilmark betraying a roughly circular enclosure, the kind of feature that typically indicates a ringfort or related settlement enclosure, a class of monument built across Ireland from the early medieval period onwards, usually as a farmstead enclosed by an earthen bank and ditch. The Clonlahy example was apparently never prominent enough to be recorded by the Ordnance Survey mapmakers who produced the first detailed six-inch maps of Ireland in 1840, suggesting it had already lost whatever above-ground form it once held. Since the aerial photograph was taken, the area has been further disturbed; a drain cut along a northwest to southeast axis has truncated part of the site, and there is a pond roughly 28 metres to the south-southwest. What remains of the enclosure lies along the southern side of a field boundary, buried and largely erased, known now only because light and crop stress conspired, briefly, to make the invisible legible.