The ironworks was of crucial importance in the development of the ability to use cheap, low quality, high sulphur iron ores worldwide.

Blaenavon Ironworks was the first in Wales to be designed as a multi-furnace site from the outset, with three furnaces, calcining kilns, workers’ accommodation and a company shop.

[5][6] William Coxe visited Blaenavon during 1798–99 and enthusiastically described the small town as “an opulent and increasing establishment, ...surrounded with heaps of ore, coal and limestone”.

The nature of the work introduced to Blaenavon was different including changes to the coal-using technology and the application of steam power, not used until that time in the Eastern Valley.

By 1833 the company owned 430 houses and employed 1000 workers but suffered a periodic boom-and-bust economy that accompanied iron-making with wage cuts, strikes, and the emergence of "Scotch Cattle".

[10] Led by new managing director James Ashwell, a huge investment was made in the ironworks, including the construction of the impressive balance tower which utilised a water displacement lift to carry pig iron from the base of the site to the Brecknock and Abergavenny Canal system, which offered lower tolls to Newport than the Monmouthshire Canal.

[11] In the following years, iron rails produced at Blaenavon were exported all over the world, including India, Russia, and Brazil; but also in projects closer to home such as the construction of Crumlin Viaduct.

It was claimed, however, that this was the consequence of workmen refusing to submit to a reduction in wages, which the depressed state of the iron industry had rendered necessary.

[14] This was short lived as it meant Germany and North America were now able to utilise their own phosphoric ores which accelerated the decline of Blaenavon Ironworks.

The forges at the site were still being used and helped with the production of steel shell during both world wars but was mostly used as a storage yard for the National Coal Board.

In 1959 novelist Alexander Cordell set his most famous novel, Rape of the Fair Country at the ironworks and in the surrounding area at the height of the industrial revolution.

[24] The remainder are listed at Grade II including: the Chain Store,[25] the Calcining Kilns,[26] a Storage Shed,[27] the Pay Office,[28] Stack Square,[29] and a memorial to the Gilchrists.