Builth Wells (Welsh: Llanfair ym Muallt) is a town in Powys, traditional county of Brecknockshire, mid Wales, lying on the River Wye.
Builth Wells grew as a market town and spa, and is known as the location of the Royal Welsh Showground, home to the Royal Welsh Show (although the showground is actually over the river Wye in
Llanelwedd, Radnorshire). The town in served by Builth Road railway station on the Heart of Wales Line, which is located just over a mile to the north, having lost its more central railway station on the Mid Wales Railway in the 1960s.
