The fortunes of the ironworks had declined by the late 19th Century
The importance of an ironworks once owned by a famous industrial family has been recognised as part of a scheme to mark famous people, events and places.
Hirwaun Ironworks, founded in 1757, is one of 30 sites in Rhondda Cynon Taf to be commemorated with a blue plaque.
The ironworks was bought by ironmaster William Crawshay, who built Cyfarthfa Castle in Merthyr, in 1819.
The works, which once produced thousands of tons of iron each year, was abandoned in 1905.
Rhondda Cynon Taf council is placing blue plaques around the county borough for a heritage trail which includes the Tonypandy Riots and the Pontypridd birthplace of opera singer Sir Geraint Evans.
More than 180 nominations were received from local residents.
Famous figures remembered include chartist, surgeon, druid and pioneer of cremation Dr William Price, and Elizabeth Andrews from Ton Pentre in the Rhondda, who was a social reformer and the Labour Party's first woman organiser.
The ironworks is one of a number of historic buildings to be recognised. Others include Nantgarw China Works and Gadlys Ironworks in Aberdare.
The village of Hirwaun in the Cynon Valley grew from the need to provide houses for workers at the ironworks.
The works had mixed fortunes under various owners until it was bought by William Crawshay in 1819.
New furnaces were built and the amount of iron produced increased dramatically in the 1820s.
During the 1830s and 40s the works were managed by William Crawshay's son Francis and much of the output was sent to another Crawshay works at Treforest near Pontypridd.
The Crawshay family closed the ironworks in 1859 and although efforts were made to revive it, the site was abandoned in the early 20th century.
The blue plaque has been erected on Ty Mawr, the ironmaster's house built in 1784 by Hirwaun Ironworks owner Anthony Bacon.