The cairn measures roughly four and a half metres across and just sixty centimetres high, a modest presence by any reckoning, but cairns of this kind were not built to dominate. They were built to mark, to cover, or to remember, and this one, however worn by time, still holds something of that original intention.

Around the edge of the mound, a scattering of larger displaced stones hints at what may once have been a kerb, the ring of upright or closely set stones that prehistoric builders used to define and contain a cairn's boundary. If that interpretation is correct, the structure has slumped and shifted considerably over the centuries, its outer frame collapsing inward or outward until only the suggestion of it remains. Cairns of this type appear throughout Ireland and are generally associated with prehistoric funerary or ceremonial activity, though without excavation it is rarely possible to say more than that with confidence. The slope at Knockatillane offers no dramatic backdrop or commanding summit view; the cairn simply exists on its quiet incline, which in its own way makes it feel more honest than the grander monuments that attract crowds.