cathedral town, Powys county, historic county of Brecknockshire, Wales, on the River Usk at its confluence with the Honddu and Tarell. The town grew up around a Norman castle built in 1092. The Benedictine Priory of St. John was founded about the same time; the former priory church, dating from the 13th century, became in 1923 the cathedral for the newly constituted diocese of Swansea and Brecon of the Church in Wales.

By the 15th century a cloth trade had become established, and by the early 16th century Brecon had become one of the most important towns in Wales, lying on the main route across southern Wales from London to Fishguard. In 1542 Henry VIII set up a chancery and exchequer at the castle and converted an earlier Dominican friary into a collegiate church and school (Christ's College). In 1797 construction was begun on a canal that would extend to Newport. Thirty-seven miles of this waterway have been restored, including an aqueduct that crosses the River Usk. The town lost its premier status in the southeast to Cardiff during the Industrial Revolution, but it has retained some importance as a shopping and service centre. Brecon was the county town (seat) of the historic county of Brecknockshire. Pop. (2001) 7,901.