The hill is recorded on the older Ordnance Survey six-inch maps under the name Knockadoon, and it is here, in ordinary pastureland, that a ringfort of the type known as a rath quietly persists, much reduced from whatever it once was.

A rath is an enclosure, typically circular or roughly so, defined by an earthen bank and an outer ditch, used in early medieval Ireland as a farmstead or the residence of a person of some local standing. The example at Shanbally is subcircular in plan, measuring roughly 23 metres north to south and 20 metres east to west, dimensions that place it within the smaller end of the rath spectrum. What defined it, a scarp on the inner edge and an external fosse or ditch on the outer, has not fared well over the centuries. The fosse is now being used as a trackway running from the north-east around to the south, a practical piece of agricultural repurposing that has done little for the monument's legibility. A gap of about 3.5 metres in the south-east arc may represent the original entrance, though time and use have made certainty difficult.