The only record of it as a distinct archaeological feature comes from the 1834 edition of the Ordnance Survey six-inch map, where a small circular outline, roughly twenty metres across, is labelled in gothic lettering as a 'fort'. Today, standing in the surrounding pasture, there is nothing to see. No earthwork, no bank, no trace of whatever once justified that designation.

The Ordnance Survey's early nineteenth-century mapping of Ireland was an extraordinarily systematic undertaking, and the surveyors who worked through Monaghan in the 1830s were generally careful to distinguish features they could observe on the ground. The gothic lettering used for 'fort' was a conventional notation for antiquities, applied to the kind of small circular enclosure, often an early medieval ringfort, that dots the Irish countryside in the thousands. Ringforts were typically defined by an earthen bank and ditch enclosing a farmstead, and they survive in great numbers elsewhere. At Aghaboy, the feature sat just north of the summit of a small north-to-south ridge, a position that would be consistent with such an enclosure. Whether it was levelled by later agricultural work, or whether the 1834 surveyors recorded something that was already barely visible, is not known. By the time the site was examined more recently, nothing remained at ground level to confirm what they had seen.