El Volcán is where the Cajón del Maipo starts to feel like proper mountain country. At fourteen hundred metres, the valley has narrowed into a gorge, the walls are bare rock and scree, and the peaks at its head, including the volcano that gives the village its name, stand above the snowline for much of the year. Few people live here, and the settlement has an end-of-the-line feel that suits the setting.
There was once a railway. In the early twentieth century a line was built from Puente Alto up the valley to El Volcán, carrying passengers and freight, including the materials for hydroelectric schemes and the produce of the mines, and it ran until the 1980s. You can still trace its course along the valley in places, as embankments, bridges and the odd station building, and the memory of it is part of local identity. The valley's story is mostly one of water, rock and effort: the dams, the tunnels, the mines and the people who worked in them.
The road beyond San José de Maipo becomes quieter and more demanding. The surface can be rough in places, particularly after winter, the bends tighten, and there are stretches with steep drops beside the tarmac and no barrier. Keep your speed under control and watch for falling rocks, particularly in spring and after rain. Altitude brings its own problems, since temperatures can drop sharply, and a clear sky in the afternoon can turn into a freezing evening. The light, though, is superb, with the high peaks catching the last sun long after the valley floor has fallen into shadow.
Beyond El Volcán, the road continues toward the hot springs and the high valley around Baños Morales, and then the surface deteriorates, so be sure of your bike and your tyres before you carry on. Services are very limited in this upper part of the valley: there is no reliable fuel, and the few shops and restaurants are seasonal. Fill up in San José de Maipo or before, take food and water, and tell someone where you are going. In winter the road can be affected by snow and ice, and sections may be closed, so the best months for the ride are late spring to early autumn.