Decazeville was originally called La Salle but was renamed after the Duke of Decazes the founder of the C19th factory that created the town.

Built on coal, the town produced coal since the 16th century. It was exported in small quantities to Bordeaux. Decazes inherited the mines and in 1826 created, with the help of a technician named Cabrol, the "Houillères et Fonderies de l'Aveyron" (Mines and Foundries of Aveyron) which developed to make this once small village a centre of ironworking and industry.