The mound is small, around five metres in diameter and half a metre high, ringed by a low earthen bank and a shallow internal fosse, the term for the ditch-like depression that typically runs just inside such an enclosure. Taken alone, it would be easy to overlook. But it is one of six such circular features recorded in the same area, and together they point to something considerably older and more significant than the label attached to them suggests.

When the Ordnance Survey mapped this part of Cavan in 1836, and again in 1876, all six enclosures were grouped under the collective name Cromwell's Camp. This was a common enough habit among nineteenth-century mapmakers, who frequently attributed mysterious earthworks to Oliver Cromwell or his campaigns, partly because his military presence in Ireland loomed large in folk memory and partly because no better explanation was to hand. In reality, the cluster of small circular mounds at Cargagh almost certainly has nothing to do with Cromwellian military activity. The form and arrangement of the features are far more consistent with a barrow cemetery, a grouping of prehistoric burial mounds of the kind found across Ireland from the Bronze Age onward. The misattribution survived on maps for decades simply because no one looked too closely.