[1][2] The road starts at Thonon-les-Bains and climbs via Les Gets and Cluses.
It then heads to Saint-Gervais and Megève, over the Col des Saisies (1,633 m (5,358 ft)).
The road then crosses the Col de l'Iseran (2,770 m (9,090 ft)).
The road heads to Briançon and then over the Col d'Izoard (2,361 m (7,746 ft)).
The road then heads through Embrun and over the Col de Vars (2,111 m (6,926 ft)) and onto Barcelonnette via Jausiers, where the choice can be made to turn south over the Col de la Bonette (2,802 m (9,193 ft))—with access to the highest paved through road in Europe, the Cime de la Bonette—or continue via the Col de la Cayolle (2,327 m (7,635 ft)).