Thousands of these sites survive across the island, but most have been softened by centuries of farming until they are barely legible to an untrained eye. The example at Ardnagragh belongs firmly to that category: by the time it was formally described in 1971, the defining earthworks had already been reduced to a barely perceptible scarp on one side and almost nothing at all on the other.

The monument was recorded as a roughly circular enclosure, measuring approximately 28 metres east-northeast to west-southwest and 26 metres north-northwest to south-southeast. A rath of this kind would originally have consisted of a raised bank, or scarp, encircling a domestic interior, often with a fosse, a defensive or drainage ditch, dug around the outside. At Ardnagragh, the external fosse remains visible along the southern and western arc, and the interior retains a gentle slope facing west-southwest, which may reflect the original choice of ground for drainage or aspect. The northern and eastern sections of the scarp have been almost entirely levelled, most likely through repeated ploughing or land clearance over the centuries, and no entrance feature can be made out. What survives is, by the standards of the record, a notably denuded example, more geological memory than monument.