Landscape view at the bottom of Pistyll Rhaeadr waterfall in Llanrhaeadr-ym-Mochnant, Wales, United Kingdom. Pistyll Rhaeadr, meaning ‘spring of the waterfall’ is a waterfall, located a few miles from the village of Llanrhaeadr-ym-Mochnant in Powys, Wales, twelve miles west of Oswestry. Pistyll Rhaeadr is formed by water falling, in three stages, over a 240-foot cliff-face, below which the river is known as the Afon Rhaeadr.