The Épine tunnel crosses the Chaîne de l'Épine mountain in Savoie. Lyon is 125 kilometres eastbound, Chambéry is 15 kilometres westbound. The tunnel is 53 kilometres from Annecy and 71 kilometres from Grenoble. The western entrance is located less than 500 metres from the northern tip of Lac d'Aiguebelette. The eastern entrance is by the town of La Motte-Servolex.