There is no earthwork, no stone, no depression in the ground. The only evidence of its existence is a dark circular line roughly fifteen metres across, visible solely from the air, in infrared.

The feature is a ring-ditch, a type of monument typically consisting of a circular or near-circular ditch, often associated with funerary or ritual practice in prehistoric Ireland. Over millennia, the original earthwork at Cloghers levelled out completely, leaving the buried ditch to betray itself only through the crops growing above it. Soil that once filled a ditch retains moisture differently from the compacted ground around it, and in dry conditions that difference shows up in the growth rate of whatever is planted there, producing what archaeologists call a crop mark. The Cloghers example came to light through infrared aerial photography carried out as part of the National Coastline Survey, and was later examined by Michael Connolly as part of his 2008 doctoral research at University College Cork into the prehistoric settlement of the Lee Valley around Tralee. The site is described as sub-circular, meaning slightly irregular rather than a perfect ring, and the dark line it produces in aerial imagery is clear enough to be mapped with some confidence despite the complete absence of anything visible at ground level.