Ruta Nacional 40 Paso del Portillo de Piuquenes

The Paso del Portillo de Piuquenes cuts through the high Andes at 4,080 meters, following ancient Inca trade routes and 19th-century mule trains that hauled silver from Potosí. This remote crossing point sits between Argentina’s Catamarca Province and Chile’s Atacama Desert, where glacial runoff carves through volcanic scree and the air gets thin enough to make your engine struggle. The route branches off Ruta Nacional 40 near Fiambalá, climbing through switchbacks carved into loose volcanic rock before reaching the windswept pass marked by a simple cairn and scattered mining equipment.

This is serious high-altitude driving requiring a well-tuned 4WD with good brakes and spare parts. Weather changes fast above 3,500 meters — summer storms can dump hail and snow even in December. Fuel up in Fiambalá and carry extra water; the nearest services are 150 kilometers away. Best tackled April through October when the pass isn’t buried in snow. What you get is raw Andean wilderness, views across the Puna plateau, and the satisfaction of crossing one of South America’s most remote international borders the way muleteers did 200 years ago.