Builth Wells was founded by the Normans when Phillip de Braose constructed a timber Motte and Bailey Castle at a commanding point overlooking the ancient crossing of the Wye.

Edward 1 rebuilt the early Norman fortress as a stone castle in 1277 however today no traces apart from the castle mound remain. It was beneath the shadow of that castle that the town developed, and took its name from the church dedicated to St Mary, that was established beyond the castle walls. The town therefore became know as Llanfair Ym Muallt – St Mary’s in the Cantref of Builth.

It is said that when the plague – The Black Death ravaged Builth in the 1350's, people living in the surrounding countryside left food and provisions for the townspeople on the banks of a brook to the west of the town. In return the inhabitants of Builth threw money to pay for the goods into the brook in an attempt to prevent the spread of plague. That brook, to this day is known as "Nant yr Arian" or "the Money Brook".

A new bridge on the present site was constructed in 1779, and coupled with the development of the new road linking north and south Wales in the 1820s, catalysed further substantial growth of the town. Most of the Builth town as seen today dates back to Victorian and Edwardian times when the discovery of health springs in the area gave the town a new lease of life.

The first recorded mention of the mineral waters at Builth dates as far back as 1740. How ever it was not until the development of Park Wells with its saline water and the Glanne Wells with its sulphur content in the 1830s that Builth’s reputation as a spa town flourished.

A tourism industry was born and during the second half of the nineteenth century large numbers of visitors came to 'take the waters'. This industry was further supported by the arrival of the railways in 1860. It is at this time that the word 'Wells' was added to Builth.

Nowadays, Builth is an interesting market town which plays host to Wales' Royal Agricultural Show in July each year, and any number of other smaller shows and fairs throughout the year. It provides an excellent base for exploring the beautiful countryside – whether on foot bike or on horseback – and for delving into the history of Wales' last prince, Llewellyn, who was killed just outside Builth in December 1282.

An impressive monument to Llewellyn is located in Cilmeri where he fell, a ten minute drive from the town.

The Wyeside Arts Centre provides live entertainment and cinema throughout the year.