It shows up as a cropmark, one of those ghostly outlines that appear when buried ditches or foundations cause the vegetation above them to grow differently from the surrounding land, usually because disturbed or moister soil produces darker, lusher crops. On an aerial photograph taken on the second of August 1996, this ring-ditch resolved itself out of the patchwork of fields below.

Ring-ditches of this kind are generally the eroded remains of prehistoric circular monuments, most commonly round barrows or burial mounds whose earthen banks have long since been ploughed flat, leaving only the encircling ditch as a faint signature in the subsoil. Ireland has hundreds of them documented through aerial survey, and the majority would pass entirely unnoticed at ground level. The Clashacrow example, at around fourteen metres in diameter, falls within the typical size range for such features. Without excavation it is impossible to say with certainty what the enclosure originally was or when it was constructed, but the form is consistent with funerary or ceremonial use stretching back into the Bronze Age or earlier.