The Eyrieux River runs for . It passes through three different landscapes. A plateau is found above a commune called Le Cheylard. This plateau is marked by the sugarloaf cones of old volcanoes. This land is mostly used for cattle and sheep. In its middle section, down as far as Saint-Sauveur-de-Montagut and Les Ollières-sur-Eyrieux, the river is a torrent. This means that it flows very quickly and roughly. It has a lot of flash floods. The power made by this torrent was used first for silk mills. Now it is used for micro-hydroelectricity production. It is also a popular spot for canoeists. The river never dries up in summer, because there are many dams and barrages that give it a steady flow. The lower section to the Rhône, at Beauchastel and La Voulte-sur-Rhône, opens into a valley. There are many farms in the valley. Peach orchards grow here.