The ringfort at Gortnaskeha, in north County Kerry, announces itself with nothing at all. It is, in the most complete sense, a disappeared place, known only because a cartographer working in the early 1840s drew a small circular enclosure into the northwest corner of a large field and moved on.

A rath, as this type of monument is sometimes called, was typically a circular farmstead enclosed by one or more earthen banks and ditches, the everyday dwelling of an early medieval Irish farming family. Thousands survive across Ireland in various states of preservation. The one at Gortnaskeha was recorded on the Ordnance Survey map of 1841 to 1842, but by the time the later edition of that map was produced, it had already been omitted. Whether it was levelled deliberately to reclaim agricultural ground, or simply eroded away, is not recorded. No surface trace remains today, which places it in a particular and melancholy category: sites that exist only as absences, legible in archive but invisible underfoot.

What survives, in effect, is a cartographic ghost. The 1841 to 1842 OS map becomes the primary evidence, a document in which the enclosure appears clearly enough to be measured and positioned, yet which represents almost everything now knowable about the monument. It is the kind of site that rewards not a visit to the field, where there is nothing to see, but a visit to a good map collection, where something briefly flickers back into view.