On a low knoll in the pastures of Carrowgallda in County Mayo, there is a ringfort that exists now almost entirely on paper. A rath, as these circular earthwork enclosures are known, was typically a farmstead of the early medieval period, its raised bank and ditch marking out a family's living space from the surrounding land. This one measures roughly 40 metres in diameter and commands good views in every direction, with the Gweestion River running about 200 metres to the north-east. Nothing of it, however, can be seen above ground today.

The enclosure was recorded on the Ordnance Survey's six-inch map of 1838, drawn during the first great systematic mapping of Ireland, but it does not appear on any later editions. Whether it was already fading from the landscape by the time those later surveys were made, or simply judged too indistinct to mark, the cartographic record quietly dropped it. What may survive is a single field fence that curves around the western slope of the knoll; its arc could preserve the original line of the enclosure's western edge, a boundary that has been maintained, perhaps without anyone realising why, simply because a fence needed to go somewhere. The knoll itself sits within a notable concentration of similar sites: two other raths lie within 200 metres to the south and south-east, suggesting this was once a well-settled stretch of early medieval countryside.