La Chaux-de-Fonds is a Swiss city of the district of La Chaux-de-Fonds in the canton of Neuchâtel. It is located in the Jura mountains at an altitude of 1000 m, a few kilometers south of the French border. After Geneva, Lausanne and Fribourg, it is the fourth largest city located in the Romandie, the French-speaking part of the country, with a population of.