The Écrins massif is part of the Dauphiné Alps themselves located in the Western Alps, one of the three subdivisions of the immense Alps massif that extends over more than 620 mi (1,000 km) and eight European countries between Genoa in Italy and Vienna in Austria. The Western Alps culminate at Mont Blanc (15,770 ft / 4,807 m) and form an arc between the Rhone Valley and the Aosta Valley, from the Mediterranean Sea to the Col Ferret between Switzerland and Italy.