The abundance of coal, ironstone, limestone and timber - all the ingredients of iron production - added to a reliable supply of water meant that the area around where Blaenafon (welsh for 'source of the river') now stands was worked from an early date, possibly pre-Roman. There was a forge at Pontypool in 1425 which may have been supplied from further up the valley, but certainly by the mid 16th century, contracts were being exchanged for the exploitation of minerals and timber at Blaenavon and workers started moving in. By 1748 there were enough inhabitants to send 48 children to the local school.

Blaenavon as a town is generally agreed to have been founded in 1787, when Thomas Hill, Thomas Hopkins and Benjamin Pratt leased some seven square miles of moorland in Lord Abergavenny's Hills from the Marquis of Abergavenny, displacing the existing tenant farmers in the bargain. Iron had been produced from blast furnaces for a long time, but these were small and powered individually by waterwheel. These three businessmen from the Midlands had a plan to build the first plant in Wales with several furnaces together using the new steam engine - increasing output considerably and at lower cost. The site at Blaenafon suited their purpose admirably.

In 1789, the first pigs of iron (so called because of the supposed similarity to a litter of piglets feeding from a sow) were produced at Blaenavon and the bonanza began. The world at this time was greedy for iron - America was recovering from the Revolution, and across the channel in France they had much need of munitions as their civil war rampaged. A mere seven years later, Blaenafon was among the top producers in Wales turning out five and a half thousand tons a year. The development of the canal system, particularly the opening of the Brecknock and Abergavenny canal meant that there was access to new markets for as much coal and iron as could be produced.

All this industry obviously required a sizeable workforce, with immigrant labour coming in from all over Wales and nearby England (the proximity of which has always had a diluting effect on the 'Welshness' of Monmouthshire and particularly Blaenavon). Housing sprang up, the first being adjacent to the ironworks at Engine Row and Stack Square (pictured, where the remains of the huge chimney is visible). Luckily, some of these still stand and can be visited at the Old Ironworks site. There is also an excellent example of an early row of workers' cottages at Cwmavon. Later the classic terraced streets that still make up much of Blaenafon were built and the town expanded dramatically.

By the mid 19th century the railway had arrived and Blaenafon itself was going full steam. New forges were built near the tracks at Forgeside and the Blaenavon Coal and Iron Company went from strength to strength. Unfortunately it was not to last and the days of Blaenavon as an industrial giant were already numbered. In 1876 two cousins, Percy Carlisle Gilchrist and Sidney Gilchrist Thomas were experimenting at Forgeside in an attempt to improve the Bessemer Converter used for producing steel in bulk. By chance, Bessemer had used Blaenafon iron in the development of his process without realising that it was particularly free of impurities. When the Bessemer Converter was used with the more ubiquitous phosphorus tainted iron-ore elsewhere it was found to be ineffective. The race was on to improve the system and two years later, after much trial and tribulation, these young Blaenafon men emerged the winners.

Whether they realized that their work would lead to the rapid collapse of the British steel industry is not known, but by the turn of the century the two biggest export markets, Germany and the United States, had managed thanks to the Gilchrist's work to be largely self-sufficient and the shipping of steel from Blaenafon was severely curtailed. The last furnace was blown out in 1904. However, by now Blaenavon was a well established community - the massive Workmen's Hall and Institute had opened in 1894 and the thriving coal mining industry still offered employment to a great number of people. Large Edwardian houses were built to house the managers of the factories and businesses that grew around the town.

The population reached a peak of 12,500 in 1921, but the granting of the Ruhr Valley coal fields to France after the Great War had hit coal exports and the next decade or more was economically dire for the town. By the start of the Second World War the population had shrunk by a third, but this did mean that the terraced houses, grossly overcrowded when a huge labour force was required, became comfortable family homes owned by their occupants. After the war many Blaenafon residents were travelling out of the town to work in the new industrial areas being developed nearby, such as Ebbw Vale and Llanwern steelworks and Blaenavon became the dormitory town it has largely remained. The ailing local mining industry finally expired in 1980 when the last seam of coal ran out.

All sorts of government grants attempted to draw employment to the area without success. However, the spirit of the town survived, and thanks to some imagination by local government and a large amount of central government and EC funding, Blaenafon is rapidly restoring lost pride as it strives once again to become a world-class town.