No earthwork breaks the surface, no stones protrude, no depression in the ground gives it away. The only evidence of its existence is a cropmark, a faint signature readable only from the air, where differential growth in the vegetation above betrays the outline of an ancient fosse, the type of defensive ditch that typically defined a ringfort.

A ringfort, to give the broader context, is an enclosed settlement of early medieval Ireland, usually circular, bounded by one or more earthen banks and ditches. Thousands survive across the country, though many, like this one, have been reduced by centuries of agriculture to the point of invisibility at ground level. Here in Killoughter, the enclosure is further interrupted on its western side by a field boundary that cuts straight through it, truncating the circuit. The aerial photograph that revealed its outline was taken under conditions where the buried fosse retained enough moisture to nourish the crop above it differently from the surrounding soil. What complicates matters further is identity. When John O'Flanagan compiled his Ordnance Survey letters in 1928, he noted a large ringfort in the adjacent townland of Rathmore. Whether he was referring to this site, or to a separate feature in the next field to the west, has never been conclusively settled. That neighbouring site, recorded under Rathmore, remains a distinct possibility, and the two may have coexisted within the same gently undulating landscape.