Part of the main chain of the Alps, lying on the borders of France and Italy. The Cottian Alps extend from the Graian Alps on the north to the Maritime Alps on the south, and form a division of the western Alps, distinct from the Dauphiné Alps to the west. The range has more than 30 peaks exceeding 3,300 m/10,827 ft, of which the highest is Monte Viso (3,841 m/12,602 ft).
There are some 20 passes or cols, among which is the pass of Montgenèvre, between the Cottian and Graian Alps, connecting the river valleys of the Dora Riparia in Piedmont and Durance in the Hautes-Alpes. This is one of the oldest of the Alpine passes, and is the lowest road in the western Alps. It is believed to be the route used by in the 3rd century BC by the Carthaginian general Hannibal when he crossed into Italy.
Other peaks include Aiguille de Scolette (3,505 m/11,499 ft), Aiguille de Chambeyron (3,400 m/11,155 ft), Rognosa d'Etache (3,385 m/11,106 ft), Dents d'Ambin (3,382 m/11,096 ft), Rochebrune (3,324 m/10,905 ft), and Rognosa di Sestrières (3,279 m/10,758 ft). The Mont Cenis pass (2,100 m/6,890 ft) between Susa and Modane was constructed by the French emperor Napoleon between 1802 and 1810 and was once the most used roadway of its time. The railway tunnel of Mont Cenis, 13 km/8.5 mi long, passes under the Col de Fréjus about 24 km/15 mi away. The tunnel was opened in 1871. The peak of Mont Cenis rises to 3,320 m/10,892 ft. Other passes are the Col de Longet, Col d'Agnello, Col de la Traversette, Col de Sestrières, and the Col des Echelles.