In a field in County Kildare, an ancient enclosure exists without so much as a raised bank or a scatter of stone to betray it. The only way to see it is from the air, and even then only under the right conditions, when the crop growing above it yellows or ripens unevenly, tracing the outline of something long buried beneath. What appears is a large oval shape, estimated at roughly 70 metres in length and 55 metres in width, its boundary defined by a back-filled fosse, that is, a ditch that was dug, used, and then deliberately or gradually filled in, leaving the soil above it with a slightly different composition from the ground around it. That difference is enough, in a dry summer, to show up in aerial photography as a cropmark, the faint but legible signature of a feature that no longer has any surface presence at all.

The enclosure at Aghanure came to attention through an aerial view on Bing Maps, noted by P. Reid, and was recorded in 2014. Beyond its dimensions and the fact that the land is under tillage, very little is documented about its origins or purpose. Oval enclosures of this general scale appear across Ireland in a range of periods, from the prehistoric through to the early medieval, and could variously have served as settlement enclosures, ritual sites, or livestock enclosures. Without excavation, the date and function of this particular example remain open questions. What is clear is that it survived, in some form, beneath centuries of ploughing, its fosse compacted but not entirely erased.