Llangadwaladr (), formerly spelt Llancadwaladr in some sources, is an isolated mountain parish in Powys, Wales. It was formerly in the historic county of Denbighshire, and from 1974 to 1996 was in Clwyd. Some 7 miles west of the nearest town, Oswestry, it covers an area of sparsely settled hill farming country around the valley of the Afon Ysgwennant beneath Gyrn Moelfre.