Ocna de Fier (Hungarian: Vaskő, German: Eisenstein) is a commune in Caraș-Severin County, in the Banat region of southwestern Romania.

Along with the Dognecea area, Ocna de Fier is among the few settlements in the world that supported almost continuous mining for some 4000 years.

[2] Archaeological evidence shows that mining in the area dates back to the Bronze Age (1900–1700 BC).

At Cracul cu Aur (Romanian for "Golden Tributary"), north of Ocna de Fier, old Roman gold mining galleries can still be seen.

The Constantin Gruescu Iron Aesthetic Mineralogy Museum is located in Ocna de Fier.