No earthwork, no ditch, no trace of a bank. And yet, somewhere in this flat to gently rolling landscape of County Sligo, a ringfort once existed, known and mapped and then, at some point between the nineteenth century and the present, lost entirely to the surface record.

Ringforts, roughly circular enclosures defined by one or more earthen banks and ditches, were the most common form of rural settlement in early medieval Ireland, likely occupied between around 500 and 1200 AD. Thousands survive across the country, many still visible as raised rings in farmland. The Cartronabree example was recorded on the first edition Ordnance Survey six-inch map, produced in the 1830s, where it appears as a hachured enclosure, meaning the cartographers indicated its shape and relief through short radiating lines rather than a solid outline. That cartographic ghost is now the primary evidence for its existence. Whether it was levelled by agricultural improvement, eroded gradually, or simply missed in later field surveys, the notes do not say.