Builth Wells is a market community and neighborhood in the region of Powys and also historic area of Brecknockshire (Breconshire), mid Wales, existing at the assemblage of rivers Wye as well as Irfon, in the Welsh (or top) part of the Wye Valley. It has a population of 2,568. Most of the town's buildings, consisting of the 1876 Market Hall, were built from stone from Llanelwedd Quarry. Much of the encountering as well as various other clothed stone used in the construction of the Elan Valley dams was also quarried right here. The quarry created the first occurrence of laumontite in Wales. The quarry is currently operated by Hanson Aggregates. Builth is a longstanding anglicization of the Old Welsh Buellt/Buallt which combines bu be, equivalent to some Middle English orthography), indicating "ox" with gellt (later gwellt), implying "lea or leas"; the same form is utilized regardless of gender of the pet. The community added "Wells" in the 19th century when its springtimes were advertised as a site visitor tourist attraction. Its modern-day Welsh name Llanfair-ym-Muallt suggests "Saint Mary in Ox Leas".