There is nothing to see if you stand in the field; the earthwork was levelled at some point and left no trace on the surface. Yet the site persists in the archaeological record precisely because of what aerial photography can reveal that the eye on the ground cannot.

A rath, as this type of monument is sometimes called, was a roughly circular enclosure defined by an earthen bank and an outer ditch, known as a fosse, used in early medieval Ireland as a farmstead or settlement. At Dromroe Commons, the enclosure measured approximately twenty metres in diameter, and it appears as a neat hachured circle on Ordnance Survey six-inch maps from 1842, 1905, and 1937, meaning that for nearly a century of mapping it was still a recognisable feature of the landscape. At some point between the later twentieth century and recent survey, it was levelled entirely. What remains of it now is a cropmark, visible in aerial photography, where the buried bank and fosse cause subtle differences in how vegetation grows above them. The soil above a filled ditch tends to retain more moisture, producing a slightly lusher or differently timed crop growth that, from the air, outlines the original shape with surprising clarity.