In a field of improved pasture in Mountaincommon, County Mayo, there is a ringfort that no longer exists as anything you could touch or stand beside. A rath, in the most basic sense, was a circular earthen enclosure used as a farmstead in early medieval Ireland, its raised banks and ditches defining a domestic world of several centuries ago. This one has been levelled so completely that there is no visible trace remaining at ground level.

What survives is cartographic rather than physical. The Ordnance Survey six-inch maps of both 1838 and 1919 record a roughly circular enclosure approximately 35 metres in diameter, its presence acknowledged by two separate surveys conducted eighty years apart. By the time of both surveys, the enclosure had already been partly absorbed into the working landscape; its south-western to northern arc had been incorporated into later field boundaries, and the townland boundary itself runs along the north-western curve, suggesting the old earthwork had been quietly recruited into the administrative and agricultural geometry of the area long before it was erased entirely. The coincidence of a townland boundary with the arc of a ringfort is not unusual in Ireland, where ancient enclosures often survived long enough to anchor later divisions of land, even as the structures themselves disappeared.