When the Ordnance Survey recorded the area in 1839 during the first great mapping of Ireland at six-inch scale, the enclosure measured roughly 48 metres on each side, oriented along a northwest-southeast and northeast-southwest axis. By the time the revised edition was produced between 1899 and 1902, the same feature was being described simply as a small, roughly square field, its original character already fading into the agricultural landscape around it.

Enclosures of this kind are common enough across the Irish countryside that they often go unremarked, yet they represent a significant category of early settlement and land use. They may be prehistoric, early medieval, or later in origin, and without excavation it is rarely possible to say with certainty what purpose a particular example served. What the Kilmanaheen enclosure has in common with many others is the way it has been absorbed rather than erased. Satellite imagery from 2011 shows that the western bank has been levelled entirely, but the remaining three sides continue to function as field boundaries, their original earthworks now doing the quiet, practical work of dividing one farmer's land from another.