A single stone rising just over a metre from the ground does not demand attention in the way that a megalithic tomb or a round tower might, yet the standing stone at Knockatrellane carries the particular quiet weight of something placed with deliberate intention. It sits on the western side of a slight col, that shallow saddle of land between two higher points where travellers and routes have always tended to converge, and it is oriented roughly north to south, as though marking a line that once meant something to whoever set it upright.

The stone itself is conglomerate, a rock type formed from compressed fragments of older material bound together over geological time, and it measures roughly 0.8 metres by 0.6 metres at its base, reaching a height of 1.05 metres. What gives it an added layer of interest is its proximity to a possible hillfort, the remains of which lie approximately 200 metres to the northeast. Hillforts are generally understood as enclosed settlements or defended high points dating from the Iron Age, though the relationship between a standing stone and any nearby enclosure is rarely straightforward. Whether the stone predates the hillfort by centuries or was in some way associated with it is not recorded. The geography, though, suggests the col itself was a place of some significance, a point where the landscape briefly opens and routes through the hills would naturally have crossed.