No earthwork, no stone, no visible boundary. What exists instead is a ghost in the grass, a circle roughly eighteen metres across that becomes legible only from the air, when the soil above an ancient ditch betrays itself through differential crop growth. These cropmarks appear when buried features, in this case a single fosse, or ditch, dug in a continuous ring, cause the vegetation above them to ripen at a slightly different rate than the surrounding soil. Seen from above at the right time of year, that difference resolves into a shape.

Ring-ditches of this kind are generally understood to be the eroded or buried remains of prehistoric funerary or ceremonial monuments, sometimes the last trace of a barrow whose central mound has long since been ploughed flat. The Coolkeeran example sits on fairly level ground, and aerial photography has captured its outline clearly enough to record its diameter and the presence of a single encircling fosse. A separate enclosure lies approximately ten metres to the west, suggesting this part of Wexford may once have held a cluster of monuments rather than an isolated feature. Such groupings are not unusual; prehistoric communities often returned to the same landscape over generations, layering one monument near another in ways that are now almost entirely invisible at ground level.