Fort du Larmont inférieur, Military fort in La Cluse-et-Mijoux, France

Fort du Larmont inférieur is a bastionless fort built between 1845 and 1851 at 1,032 m on the commune of La Cluse-et-Mijoux. Its rooms are cut into the rock across six levels, and it has two single-storey barracks rebuilt in 1882. The pale grey stone walls, mostly windowless with small rectangular openings, enclose a grassy rampart.

Built between 1845 and 1851, this fort was created to defend the nearby Fort de Joux and strengthen mountain pass security during times of border tension. An explosion in 1877 severely damaged the structure, prompting a reconstruction from 1882 to 1884 that incorporated improved defensive systems.

The fort represents a physical record of how France organized mountain defense during a critical period, with its rock-cut chambers and fortified design still visible to those who explore it. The site shows the engineering priorities and building methods of that era.

The fort sits at mountain height with steep access routes, so sturdy shoes and reasonable physical fitness make the visit more comfortable. Access is limited to specific opening periods, so checking local information beforehand helps plan your visit properly.

The fort's entrance fronton carries two names: Boulanger's 1887 decree renamed it after General Jean-Pierre Firmin Malher, and though the decree was revoked that October, both names stayed carved in the stone. The 1877 blast that destroyed the buildings came from 3 tonnes of explosives seized by customs.