The Mont Blanc massif (Occitan: Massís del Mont Blanc; Italian: Massiccio del Monte Bianco; French: Massif du Mont-Blanc) is a mountain range in the Graian Alps. It is named after Mont Blanc, at 4,810.45 m[1] the highest summit of the Alps. It is located in France (Haute-Savoie and Savoie), Italy (Aosta Valley), and Switzerland (western Valais).

 

The Col Ferret separates it from the Pennine Alps; the Little St Bernard Pass separates it from the Graian Alps; the Arve valley separates it from the Aiguilles Rouges and the French Prealps.

The French side of the Mont Blanc massif is drained by the rivers Arve and Isère. The Italian side is drained by the river Dora Baltea. The Swiss side is drained by left tributaries of the river Rhône. The three borders converge near the summit of Mont Dolent.

 

Mont Blanc is crossed by a 11.6 km tunnel that connects Courmayeur (Italy) to Chamonix (France). The tunnel is infamous for an accident on March 24, 1999, when a truck ignited in the tunnel, and the resulting fire lasted 53 hours and killed 39 people.