At Kilnacappagh in County Tipperary, a semi-circular enclosure was recorded on the first edition Ordnance Survey six-inch map, the great nineteenth-century mapping project that documented Ireland's landscape in extraordinary detail. Today, nothing of it can be seen on the ground, and its status as a genuine antiquity is considered doubtful. What remains is essentially a cartographic ghost, a shape on an old map with no confirmed story behind it.

Enclosures of this kind, when they are genuine, tend to belong to early medieval Ireland, the period roughly between the fifth and twelfth centuries when circular or near-circular ditched and banked enclosures were built to define farmsteads, ecclesiastical sites, or places of local significance. A semi-circular form sometimes indicates that only part of an original ring survived into the era when surveyors first walked the land, the rest having been levelled by centuries of agriculture. In this case, however, the question of whether there was ever anything substantial here remains open. The Ordnance Survey's first edition work, produced from the 1830s onward, captured landscape features that local informants pointed out or that fieldworkers observed, but the accuracy of individual identifications varied, and some features recorded then have since proved difficult to verify.