A cropmark roughly forty metres in diameter, defined by a ditch, has been identified from aerial photography, its outline emerging in the differential growth of crops or grass above the buried feature below. Cropmarks form when buried ditches or walls affect how plants grow above them; ditches, which retain more moisture, tend to produce taller, greener growth, while buried walls cause the opposite. The result, under the right conditions of dry weather and high sun angle, is a ghostly diagram of whatever once stood or was enclosed at ground level.

The site was identified from a Bing aerial photograph, with a faint corroborating outline also visible on Google Earth imagery captured in April 2020 and again in July 2018. The circular shape, defined by what appears to be a single enclosing ditch, is consistent with the broad category of enclosed sites found widely across Ireland, ranging from early medieval ringforts to prehistoric enclosures of various kinds. Without excavation, the date and function of the Glascloon feature remain unknown. What the aerial record preserves is essentially a silhouette, the shadow of a ditch that has been ploughed flat or otherwise levelled over an unknown span of time, surviving only as a chemical and botanical signature in the soil above it.