Partly ruined Augustinian priory at the foot of Black Mountains in the secluded Vale of Ewyas, a steep sided once glaciated valley within the Black Mountains area of the Brecon Beacons National Park. It lies seven miles north of Abergavenny on an old road to Hay on Wye at Llanthony. The main ruins are under the care of Cadw and entrance is free. The priory is a Grade I listed building.
The ruins have attracted artists over the years, including Joseph Mallord William Turner who painted them from the opposite hillside. The Offa's Dyke Path National Trail runs close by on the Hatterrall Ridge above the Llanthony Valley and marks the Wales-England border here.