What was once recorded as a prostrate sandstone pillar, measuring roughly 1.78 metres long, 0.52 metres wide, and only 0.2 metres thick, and tapering toward one end in the manner of a deliberate upright, has since left no visible trace in the level pasture at the foot of a south-facing slope. Whether it was removed, buried, or simply absorbed into the working landscape of a farming field is no longer clear.

The classification of a stone like this as a standing stone rests partly on its shape. The tapered profile is characteristic of prehistoric monoliths intended to be driven into the ground with the narrower end uppermost, and sandstone pillars of this kind are found across the south-west of Ireland, often associated with Bronze Age activity in the landscape. What makes the Knockbrack site particularly interesting is its immediate context. Approximately 150 metres to the north lie two further prehistoric survivals: a rock art site and an ogham stone. Ogham is an early medieval script, typically carved as a series of notches and strokes along the edge of a stone, used mainly in Ireland between roughly the fourth and seventh centuries AD to record names, often in commemoration of the dead. Rock art, by contrast, tends to be considerably older, comprising abstract carved motifs such as cup marks and spirals whose precise meaning remains debated. The clustering of these three monuments within such a short distance of one another suggests that this corner of Knockbrack held some significance across a very long span of prehistoric and early historic time.