What makes Drumskelt unusual is not what survives but what doesn't: the only evidence that anything was ever here is a single cartographic moment, the 1834 edition of the Ordnance Survey six-inch map, where a circular embanked enclosure is marked in the formal gothic lettering reserved for antiquities and labelled, simply, as a fort.

The site sits on the local summit of a west-to-east drumlin, a low elongated ridge of glacial till characteristic of the Monaghan landscape, at the point where the ridge turns northward. That elevated position would have made the enclosure a commanding one in its time, and the choice of a drumlin summit for a ringfort, the most common type of early medieval enclosed settlement in Ireland, is entirely typical. A ringfort usually consisted of an earth bank and external ditch enclosing a farmstead, and the one at Drumskelt appears to have been a solid example at around 45 metres in external diameter. But agricultural improvement has been thorough here, and today the field shows no trace of any earthwork. Large overgrown ponds are the main features visible, the likely result of drainage work that accompanied the reclamation of the land.

The 1834 map therefore carries more weight than usual. Cartographers working on the first Ordnance Survey of Ireland recorded earthworks and antiquities with considerable care, and the gothic script notation was a deliberate convention to flag features of historical interest. That Drumskelt appears on that edition alone, with nothing surviving to confirm it on the ground today, places it in a small and melancholy category of places that existed just long enough to be noticed before disappearing entirely.