Somewhere in the fields around Grangebeg in County Kildare, the faint circular outline of what may be a ringfort shows up in aerial photography, yet no map has ever acknowledged it. The Ordnance Survey, which recorded Irish monuments across its various nineteenth and twentieth-century editions of the six-inch map series, left this spot entirely blank. Whatever lies beneath the grass, it passed unnoticed by every surveyor who ever walked the area.

Ringforts, known in Irish as ráth or lios depending on their construction, were the most common form of rural settlement in early medieval Ireland, typically consisting of a circular area enclosed by one or more earthen banks and ditches. Many thousands survive across the country, though a considerable number have been ploughed flat or built over. The possible enclosure at Grangebeg was identified not by fieldwork but from a Digital Globe aerial photograph, where cropmarks or subtle changes in ground relief can betray buried or overgrown features invisible at ground level. The site came to attention through details provided by Hugh Carey and was documented in 2018. Whether the outline represents a genuine early medieval enclosure, a later field system, or something else entirely remains an open question, one that only excavation or further remote sensing could resolve.