New Radnor was once a place of great importance, being a market, borough and county town, but has since dwindled in size and importance. There are a number of remnants of defensive strongholds on the outskirts of the town, the most significant being the site of New Radnor Castle (NPRN 306379), of which little remains. It is believed that this was the work of William FitzOsbern soon after the arrival of the Normans in Britain. In addition, there are Castell Crugerydd (NPRN 306085) and Tomen Castle (NPRN 306094).
New Radnor Castle and the planned medieval town which developed around it were besieged, demolished and rebuilt several times through the centuries, the final destruction of the castle taking place in 1401 during the uprising of Owain Glyndwr. The market town survived nonetheless, and during the reign of Henry VIII was raised to being the county town of the newly formed Radnorshire. This status was lost in 1833, however, and the market fell into disuse. Public business continued to take place in the Town Hall, which maintained its name despite New Radnor being a village by this time, but by the nineteenth century this hall was in a `very mean state of repair?. Today the village is primarily an agricultural centre.

Source: Lewis, A Topographical Dictionary of Wales, 1833

K Steele, RCAHMW, 20 January 2009