Crug Eryr Castle (Castell Crug Eryr) was a motte and bailey-style castle located atop a hill adjacent to the A44 about 2 miles northwest of Llanfihangel Nant Melan, near New Radnor in Powys, Wales. Cryg Eryr, which means "the eagle's mount," was likely situated to block the mountain pass into Maelienydd.