The
Mont Blanc Tunnel is a
highway tunnel in
Europe, under the
Mont Blanc mountain in the
Alps. It links
Chamonix,
Haute-Savoie,
France with
Courmayeur,
Aosta Valley,
Italy, via
European route E25. The passageway is one of the major trans-Alpine transport routes, particularly for Italy, which relies on the tunnel for transporting as much as one-third of its freight to northern Europe. It reduces the route from France to
Turin by and to
Milan by . Northeast of Mont Blanc's summit, the tunnel is about southwest of the
tripoint with
Switzerland, near
Mont Dolent.