A circular enclosure, roughly forty metres in diameter, was recorded on the first edition of the Ordnance Survey six-inch map, the great nineteenth-century cartographic project that captured Ireland's landscape in remarkable detail. Today, no surface trace survives. The enclosure is, in practical terms, gone.

Circular enclosures of this type are among the most common prehistoric and early medieval features in the Irish landscape. They served variously as farmsteads, ritual sites, or enclosures for livestock, and their earthen banks or stone walls were once a defining feature of the countryside. A diameter of around forty metres would be consistent with a fairly typical example. What makes the Rosscahill site quietly interesting is precisely the gap between its former presence on a map and its current absence on the ground. The OS surveyors who walked this terrain in the nineteenth century saw something worth recording, a defined circular boundary of sufficient clarity to commit to ink. Whatever it was, the scrub and grassland have since reclaimed it entirely.

That kind of erasure is not uncommon. Agricultural improvement, land clearance, and simple vegetation growth can erase earthworks that were already low-lying and subtle. The map becomes the only surviving evidence, a cartographic ghost of something that shaped the land long before anyone thought to document it.