Ruta Nacional 51 Abra del Acay to San Antonio de los Cobres

The stretch from Abra del Acay down to San Antonio de los Cobres drops you from the highest paved pass in the Americas into a landscape that looks like Mars had a baby with the moon. This section of RN51 winds through the heart of the Puna plateau, where vicuña dart between ancient mining camps and the Train to the Clouds tracks parallel your descent. The Quebrada del Toro cuts a dramatic gash through the mountains as you approach San Antonio, with the old railroad infrastructure telling stories of ambitious engineering in impossible terrain.

Moderate difficulty thanks to altitude rather than technical challenges—the road is paved but narrow with steep grades and zero guardrails in places. Any vehicle can handle it, but altitude sickness hits hard above 4,000 meters, so acclimatize first. Best tackled April through October when weather’s stable. Fuel up in Salta or Cafayate; San Antonio has limited services. This route delivers massive landscapes and mining history without requiring a full expedition vehicle.