Radnorshire () 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. The county was formed from the two cantrefs of Maelienydd and Elfael. Area 301,164 acres (1,219 km²). Population 23,000. In the east and south are some comparatively level tracts, including the Vale of Radnor, but most of the county is mountainous, with the Cambrian Mountains running through the west 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. It is said that sheep out number people in Radnorshire by 50:1 , giving it a sheep population of over 1,000,000.

Places of special interest ([[British national grid reference system|grid reference]]): Abbey Cwmhir aka Abbeycwmhir (); Beguildy Tumuli (); Broadheath House, Presteigne (); Elan Valley Visitor's Centre (); The Pales (); Offa's Dyke (, ); The Rock Park, Llandrindod Wells ().

Traditional counties of Wales | Radnorshire

Sir Faesyfed | Radnorshire