Buttevant, in north County Cork, offers something stranger: walls that are historically documented, whose general shape has been theorised, and yet which have left no confirmed physical trace whatsoever. The defences are known to have existed, and are quite possibly still out there in some form, but nobody has yet been able to point to a single surviving fragment and say with certainty, this is it.

A murage grant of 1317, a type of royal or lordly licence permitting a town to levy tolls specifically to fund the building or maintenance of walls, authorised John de Barry to enclose Buttevant with walls under his supervision. By 1375 there was at least a North Gate, suggesting the circuit was at some point complete enough to have named entrances. The enclosed area was probably rectangular, estimated somewhere between five and fifteen hectares, and there are hints in the historical record of a double-wall arrangement, an inner and an outer circuit with roughly twenty-five metres between them. Writing in 1750, the antiquary Charles Smith recorded visible remains of a wall surrounding the town, and noted traces of an outward wall beyond it that took up a considerable circuit of ground. That was nearly three centuries ago. By the time the Ordnance Survey produced its six-inch map in 1842, no town walls were marked at all. Subsequent researchers, including work by Thomas in 1992 and Cotter in 2010, have proposed possible lines for the wall, but none of these proposals has been confirmed by any surviving masonry. The walls of Buttevant remain, in a precise and slightly unsettling sense, a presence that has not yet been found.