When it was built (1876-1878), Fort Lachaux was part of the Montbéliard stronghold. In 1906, it was incorporated into the Belfort stronghold as an advanced fort. Its main role was to prevent the Belfort stronghold from being bypassed to the south and to control the crossings of the Savoureuse to the north and the Doubs to the south. It provided a link between the Mont-Bart fort to the south and the Mont-Vaudois and Bois d’Oye forts to the north. 

Its armament was reinforced by a four artillery batteries. The barracks were divided into two sections, each capable of accommodating more than 700 people. It also had an infirmary for 20 patients. The water supply was provided by two cisterns with a total capacity of 280 m³ and two wells. Left derelict after the Second World War, the fort was largely demolished in the early 1970s to make way for basic accommodation for housing Peugeot factory workers. After the demolition of part of these dwellings in 1987, the town of Grand-Charmont built a leisure centre on the site. This fortification is not open to visitors, but the association Regard Grand-Charmont brings the surrounding area to life. 

In 2017, an entertainment farm with 150 animals was set up, and in 2018 the tourist offer was extended to include 6 walking routes At present, the barracks are used by a shooting club and are the venue for an escape game.