Chaudefour valley national nature reserve

At the foot of the Sancy, the Chaudefour valley is one of the three glacial valleys of the massif, closed off by a cirque. Jagged walls, sharp peaks, peat bogs and a torrent at the bottom: the national nature reserve has protected these 820 hectares since 1991.

You start at the reserve's visitor centre (maison de la réserve), 7 km from Chambon-sur-Lac (open from May to mid-September in 2026, free entry). From there, the valley-floor path runs gently uphill to the Cascade de Pérouse and an iron-rich spring, an easy 1.5 km. At the end of those 1.5 km, at the entrance to the valley, the Cascade de la Biche can be reached in 45 minutes one way, and the ridge circuit is a 13.5 km loop in 5 to 6 hours, rising to 1,820 m at the Col du Puy Ferrand (strong walkers). There is a charge for the entrance car park from early May to the end of September (€4 for up to 4 hours, €6 beyond, 2026 rate).

At the entrance to the valley, the Dent de la Rancune and the Crête de Coq, two sharp dykes, rise above you. Access to the path that runs level with the Crête de Coq has been forbidden since 1999. On the wildlife side, chamois, mouflon and marmots were introduced here, and the Apollon arverne, a protected butterfly, is among the reserve's residents.

With hiking boots on your feet, you stay on the waymarked paths: that is the reserve's rule. Dogs are not allowed there, even on a lead.