This is a rath, the Irish term for an earthen ringfort, a type of enclosed farmstead built and occupied predominantly during the early medieval period, roughly between the fifth and twelfth centuries. Thousands survive across Ireland, most of them unexcavated, and this one at Clash is among the quieter examples, easy to overlook unless you know what the landscape is telling you.

The enclosure is roughly circular, measuring approximately 34 metres north to south and 32.4 metres east to west, which puts it within the typical size range for a single-family agricultural settlement. Its defining feature is an earthen bank, surviving to about 1.1 metres in height along the western to northern arc, accompanied by a shallow external fosse, the term for a ditch dug to provide the material for the bank itself. On the northern to south-eastern side, that bank has been absorbed into the modern field fence system, its original form subsumed into later agricultural boundaries. Elsewhere the enclosure survives only as a low rise in the ground. The whole thing sits on a south-south-west-facing slope, the kind of aspect that would have offered early medieval farmers reasonable shelter and decent light for the small cluster of timber buildings that once stood inside.