Radnorshire (Welsh Sir Faesyfed) is an inland traditional county of Wales, bounded to the north by Montgomeryshire and Shropshire, to the east by Herefordshire, to the south by Brecknockshire and to the west by Cardiganshire. Areas 301,164 acres (1,219 km²). Population 23,000. In the E. and S. are some comparatively level tracts, including the Vale of Radnor, but most of the County is mountainous, with the Cambrian Mountains running through the W. of the County. The highest point is at Radnor Forest, 2,166 ft (660 m). The Elan Valley contains several huge man-made reservoirs supplying water to Birmingham. The main rivers are the Wye, the Elan and the Ithon . The chief towns are Knighton, Llandrindod Wells, Llanelwedd, New Radnor, Presteigne and Rhayader. The main industries are tourism and hill farming.

Places of special interest (grid reference): Abbey Cwmhir aka Abbeycwmhir (); Beguildy Tumuli (SO176767); Broadheath House, Presteigne (SO3363); Elan Valley Vistor's Centre (SN927646); The Pales (SO138641); Offa's Dyke (SO2763, SO2872); The Rock Park, Llandrindod Wells (SO052609).