The Fort de Champillon is a twentieth-century Swiss fortification located in the heights overlooking the Rhône valley from the north between Montreux and Monthey. Completed in 1944, the fort secures the road and rail lines running east from Lausanne to the mountainous interior of Switzerland. The position is an advanced work protecting the approaches to Fortress Saint-Maurice, part of the Swiss National Redoubt. It is entered from the plateau just downhill from Corbeyrier, a village on the heights at the foot of the Tour d'Aï.