Stone circle below Hay Bluff , south of Hay-on-Wye , in northern Black Mountains , Powys .Marked as stone circle and sited adjacent to a car park on a minor road from Hay-on-Wye to Llanthony. This site has only recently been recognised as a stone circle: in the past it had variously been described as the remains of a cairn or burial chamber. The largest stone, on the east of the circle, is 1.5m high and 1.1m wide and has much smaller stones to either side of it which follow the arc of a circle 30m in diameter. Underneath the Ordnance Survey bench mark, a circular depression can be seen which is believed to be a cupmark, something of a rarity in this area of Wales. Four very small stones are just discernible on the opposite side of the circle with another stone to the south. The circle has an obvious entrance to the SE marked by flanking portal stones which are not a common feature amongst stone circles in Wales.