Aerial photographs taken in November 2011 already showed the workings closing in on three sides, making the monument one of the more visually incongruous survivals in the Irish midlands. A ringfort, or rath, is an enclosed farmstead of the early medieval period, typically dating from roughly the fifth to the twelfth century, and defined by one or more earthen banks surrounding a circular interior where a family and their livestock would have lived. This one in Knightswood is a substantial example, roughly 43 metres across at its widest, with its enclosing bank and shallow external ditch, known as a fosse, still legible around much of its circuit.

The site sits on the northern face of a hill summit, with higher ground rising to the west, and the bank is best preserved along its southern arc, reaching 3.7 metres in width in places. An entrance gap, just 1.8 metres wide, opens at the south, which is a typical placement for ringfort entrances, possibly for reasons of shelter or orientation. Elsewhere the bank has been levelled or reduced to a low scarp, partly the result of agricultural activity over the centuries. Inside the enclosure, traces of cultivation ridges run from northeast to southwest, suggesting the interior was at some point turned over to tillage, and an old field fence once cut across the monument from northeast to east, further evidence of the site's long post-medieval use as ordinary farmland. What makes Knightswood quietly unsettling is that the threat to the monument is not historical but ongoing. The quarry that now surrounds it on almost every side was expanding within recorded memory, leaving the rath stranded like an island in a worked-out landscape.