Ruta Provincial 40 Paso de San Francisco

The Paso de San Francisco route climbs from the desert town of Fiambalá through volcanic moonscapes to one of the highest international border crossings in the world. This remote track follows ancient Inca trading routes, passing the massive Volcán Ojos del Salado base camp turnoff at 4,200 meters before cresting the continental divide. The road deteriorates significantly after Laguna Verde, with loose volcanic scree and washouts demanding constant attention while altitude sickness becomes a real factor.

Expert difficulty due to extreme altitude, weather exposure, and zero services for 200+ kilometers. High-clearance 4WD mandatory, plus winter gear regardless of season — temperatures can drop below freezing even in summer. Border typically closed May through October due to snow. Fuel up in Fiambalá and carry extra water; the nearest help is literally in another country. Those who make it earn bragging rights to one of South America’s most challenging high-altitude crossings.