The Royal Saltworks (Saline Royale) at Arc-et-Senans, built in 1779 by Claude Nicolas Ledoux, was a factory for the production of salt by heat evaporation of salted water.
The complex consists of 11 buildings, not only workshops but also workers home, and is laid out in a semicircle around the Directors House.
It was part of a bigger, unrealised plan of a circle containing the factory as well as other buildings of the ideal city of Chaux.
The factory was in production until 1895.

The production of salt at Salins-les-Bains started more than 1.000 years ago. Salt was produced by extracting underground salted water and subsequent evaporation by heating.
The underground galleries date back as far as the 13th century, and in the 18th century a hydraulic pumping system was installed for the extraction of the underground water. The Saltworks were in operation until 1962.