La Chaux-de-Fonds District was one of the six districts of the canton of Neuchâtel, Switzerland, until the district level was eliminated on 1 January 2018. The district capital was the town of La Chaux-de-Fonds. It had a population of 39,796.

La Chaux-de-Fonds contains three municipalities:

La Chaux-de-Fonds district had a population (as of 2017) of 39,796.

Most of the population (as of 2000) speaks French (32,804 or 85.8%) as their first language, Italian is the second most common (1,344 or 3.5%) and Portuguese is the third (1,175 or 3.1%). There are 945 people who speak German and 32 people who speak Romansh.