At Glantane in County Kerry, a ringfort, the type of circular earthwork enclosure used as a farmstead during the early medieval period, was recorded on the first edition of the Ordnance Survey map and given the name "Fort" on the Fair Plan, the detailed field document drawn up during the original survey. Today, there is no visible trace of it whatsoever. The enclosure, described as univallate, meaning defended by a single surrounding bank and ditch, has been entirely absorbed back into the landscape.

The site was catalogued by J. Cuppage in the 1986 Dingle Peninsula archaeological survey, a thorough study of the Corca Dhuibhne region that documented hundreds of monuments across the peninsula. By the time that record was compiled, the earthwork had already vanished from the surface. The nineteenth-century cartographers who mapped it were therefore capturing something that later generations of land use, farming, and time itself would erase. What remains is essentially a cartographic ghost, a named feature on historic maps with nothing left on the ground to correspond to it.