Ouvrage Otterbiel, Military fortification in Bitche, France

Ouvrage Otterbiel is a Maginot Line fortification near Bitche consisting of four combat blocks and one entrance block linked by underground galleries. The facility includes ammunition storage, command posts, and observation stations within its subterranean network.

Approved for construction in August 1931, Otterbiel was planned as a gros ouvrage with an 81mm mortar turret, two 75mm gun casemates and a separate personnel entrance, but budget cuts left it a petit ouvrage. It surrendered with the Bitche fortifications on 30 June 1940, was lightly defended and captured by the U.S. 100th Infantry Division in March 1945, and was renovated by 1953 as part of the Môle de Bitche.

The ouvrage's name comes from the Grand Otterbuehl hill at cote 367, where it was built. Its five blocks are numbered and marked with the ouvrage's designation O 400, while the observation cloche in Block 4 carries the indicator O 15. The garrison in 1939 numbered 98 men and 7 officers of the 37th Fortress Infantry Regiment under Captain Le Guanec.

Otterbiel stands on military land at the western end of the Camp de Bitche, on the hill called Grand Otterbuehl at cote 367, and access is forbidden to the public. There are no guided tours and no visiting times; the site is reportedly used by the French Army for ammunition storage. Views of the exterior are only possible from outside the camp boundary.

The fortification was equipped with three separate diesel generator units, each combining an engine with an alternator for power output. This backup system ensured the facility could continue operating if any single generator failed.