The Gorges de l’Ardèche begins at the Pont d’Arc, a very beautiful 54m-high arch that the river has cut for itself through the limestone, just downstream from Vallon, itself 39km south of Aubenas. The gorge continues for about 35km to St-Martin-d’Ardèche in the valley of the Rhône.
The gorge winds back and forth, much of the time dropping 300m straight down to the almost dead-flat scrubby Plateau des Gras. It’s beautiful, but a tourist trap; the road following the rim, with spectacular viewpoints at regular intervals, is jammed with traffic in summer, when you should book accommodation well in advance. The river, down at the bottom, which is where you really want to be to appreciate the grandeur of the canyon, is likewise packed with canoes in high season.