A rath is a roughly circular earthen enclosure, typically from the early medieval period, which once served as a defended farmstead for a family of some local standing. This one measures about 57 metres across, and while its bank has been considerably denuded over the centuries, traces of stone revetment, the facing material used to reinforce an earthen structure, survive in places both along the inner and outer edges. The stretch running from the north-east to the south-east has been almost entirely levelled, which is not uncommon where agricultural activity has gradually eaten into such monuments over generations.

What makes Cahergononey particularly interesting is the detail preserved within the enclosure itself. The foundations of two rectangular houses survive: one in the south-western quadrant, oriented roughly north-east to south-west and measuring around thirteen metres long by four metres wide; another in the north-western quadrant, oriented east to west and somewhat broader at seven metres wide by twelve metres long. There is also a probable souterrain, an underground stone-lined passage or chamber often associated with raths and thought to have served for storage or refuge. A short length of low bank, about seven metres long, runs roughly north to south just east of centre, the purpose of which is not entirely clear. What was not found, despite a specific record from 1903 by a Costello, is a stone-built covered way described at that time as running for sheep under the wall. Whether it has since been robbed out, collapsed, or was simply not located on subsequent inspection, it remains an absence that gives the site a small historical puzzle to carry.