The ground gives nothing away; no mound, no ditch, no shadow in the grass to suggest that anything out of the ordinary ever stood here. And yet, in 1834, the cartographers of the Ordnance Survey recorded it clearly on their six-inch map, marking a small circular earthwork in the distinctive gothic lettering they reserved for antiquities, labelling it simply as a "fort".

The site sits on the ridge of an east-west drumlin, one of the long, smooth hills shaped by glacial deposits that define so much of the Monaghan landscape. A col is the slight dip or saddle between two higher points on a ridge, and it is precisely this kind of position, with ground falling away to the north and south and rising again to the east and west, that was often favoured for enclosed earthworks. The structure the OS surveyors recorded was modest in scale, roughly twenty metres in external diameter, the kind of embanked ringfort that was a common feature of early medieval Irish settlement. At some point after 1834, a road cut through the southern edge of the earthwork on a roughly east-north-east to west-south-west alignment, truncating whatever remained. Today, even that truncated outline has vanished beneath the pasture.