La Chaux-de-Fonds (French: [la ʃodəfɔ̃]; archaic German: Schalu; Arpitan: La Châls) is a Swiss city in the Canton of Neuchâtel . It is located in the Jura Mountains at an altitude of 992 metres, a few kilometres south of the French border. After Geneva, Lausanne, Biel/Bienne , and Fribourg, it is the fifth-largest city in the Romandie, the French-speaking part of the country, with a population (as of December 2020) of 36,915.

The city was founded in 1656. Its growth and prosperity are mainly bound up with watchmaking. It is the most important centre of the watch-making industry in the area known as the Watch Valley.