Fort de Chelles, Military fortress in Chelles, France.

Fort de Chelles is a pentagonal fort oriented east, built at 104 metres on the commune's highest point, the "montagne". Its casernement has seven bays with one storey, the bay interiors built of terracotta brick. The fort held 363 men and 29 artillery pieces, and has three caponnières, two single and one double, blackened by fires lit during firefighter training.

The fortress was built between 1876 and 1879 as part of Paris' defensive system. It was constructed during a period when France needed to reinforce its borders after the war of 1870.

The fort displays principles of French military architecture from the 1870s. It reflects the strategic thinking that guided Paris' defense planning during that era.

The fort stands on the "montagne" of Chelles, the town's highest point at 104 metres, and since 2007 the surrounding hill has been laid out as a park for walks and municipal events. The fort buildings themselves are walled up and closed to the public, so the grounds can be seen but the interior cannot be entered.

The fort's entrance once carried a fronton inscribed "Fort de Chelles" with the dates "1876 - 1879". It was dismantled in the 1960s and 1970s so that taller vehicles, including Kodak trucks, could pass through.