Megalithic monuments, a broad category covering everything from portal tombs and passage graves to stone circles and standing stones, were typically raised during the Neolithic and Bronze Age periods, roughly between five thousand and three thousand years ago. Mayo has a notable concentration of such remains, shaped in part by the county's long history of human settlement and by the relative survival of upland and marginal terrain that was never heavily developed in later centuries. What makes this particular structure quietly unusual is how thoroughly it has slipped from view, not physically, but documentarily.