The extent of the area designated as Fortress Saint-Maurice is not clearly defined, but according to the Association Fort de Litroz, the Saint-Maurice sector comprises the Rhône narrows from just north of Saint-Maurice to Martigny, excluding Chillon and Champillon, as well as the fortifications of the lateral valleys.
Their unit ships out to France, where they are billeted at a farm in the village of Champillon in the Marne.