That typographic choice was deliberate: gothic script on early OS maps was reserved for antiquities, signalling to any reader that the feature pre-dated living memory and carried some quality of the ancient. By 1907, the same feature had been quietly reclassified on the revised map as an ordinary subcircular field, the kind of notation that erases a place's strangeness without quite erasing the place itself.

What survives on the ground at Mullanavannog is an overgrown area roughly thirty metres across, enclosed by an earthen bank. There is no visible fosse, which is the external ditch that typically accompanies an Irish ringfort, and no identifiable entrance gap. Ringforts, the most common field monument type in Ireland, were generally farmstead enclosures built during the early medieval period, their banks and ditches marking out a defended domestic space. The absence of a fosse here makes confident classification difficult, and the site sits in that ambiguous territory between a recognised archaeological monument and a lump of ground that farming and time have rendered nearly illegible. The outer diameter was originally recorded at around thirty-five metres, suggesting a modest enclosure, and its position at the ridge crest would have given it a commanding view south across the drumlin landscape that characterises this part of Monaghan.