BLAENAFON or BLAENAVON, urban district, Mon mouthshire, England. Pop. (1931) 1,o75, in a cul-de-sac on the north-east edge of the South Wales coalfield, near the source of the Afon Llwyd. Owing to its situation on the ironfield of the northern outcrop of the coalfield, Blaenaf on, like Merthyr and Dowlais, became an important iron smelting region soon after the Industrial Revolution, famous for its iron, steel and tinplate works.