Route 40: The Backbone of Argentina
Few roads in the world boast the mystique and sheer scale of National Route 40. Stretching over 3,100 miles (5,100 kilometers) from north to south, this legendary road doesn’t just cross Argentina—it forms the very spine of the country from end to end.
A bucket-list journey for adventurers across the globe, “the forty” bridges the solitary Patagonian steppe with the fearless heights of the Puna. It hugs the Andes Mountains like a ribbon of asphalt and gravel, weaving together diverse ecosystems, ancient cultures, and millennia of history.
Driving its length reveals a geography in constant mutation, where glacial meltwater breathes life into fertile oases, and where indigenous peoples mapped out, centuries ago, the very trails we travel today.
From Ancestral Trails to Modern Legend
The history of Route 40 is a fascinating dialogue between the pre-Columbian past and 20th-century engineering. Much of its northern and central sections trace the ancient footsteps of the Qhapaq Ñan (the Inca Road Network) and indigenous trails carved by native peoples who knew the exact location of water sources with pinpoint accuracy—vital spots that eventually blossomed into today’s towns and cities.
Officially established in 1935, the route’s Kilometer 0 sat in the city of Mendoza for decades. However, in 2004, the National Highway Directorate redrew the map to unify this national corridor, moving its starting line to Cabo Vírgenes in the Santa Cruz province. From this extreme southern tip of continental Argentina—just 77 miles (124 km) from Río Gallegos—all the way up to the heights of Jujuy, the route spans 11 provinces, crosses 18 major rivers, and strings together 20 National Parks and Protected Areas.
Unlike America’s famous Route 66, Route 40 unfolds at staggering altitudes and demands serious geographical respect. It peaks at the Abra del Acay pass in Salta at a breathtaking 16,059 feet (4,895 meters) above sea level, cementing its status as the highest national highway pass in the Americas and one of the highest on Earth.
The Three Great Legs of the Journey
As you conquer Route 40, the Argentine map splits into three massive regions, each boasting a fiercely distinct personality:
Patagonia: Wind, Glaciers, and Alpine Lakes
Across the provinces of Santa Cruz, Chubut, Río Negro, and Neuquén, the landscape fiercely clashes vast plateaus and relentless winds against the jagged granite spires and lush, damp forests of the Patagonian Andes.
The epic journey kicks off at the Magellanic penguin colony of Cabo Vírgenes and pushes westward along the Río Turbio coal basin. From there, it acts as the grand entrance to Los Glaciares National Park (home to the legendary Perito Moreno Glacier) and offers a must-do detour to the imposing Pinturas River canyon to marvel at the ancient rock art of the Cave of the Hands (Cueva de las Manos). Pushing further north, the highway carves through Los Alerces National Park, the laid-back Andean haven of El Bolsón, and the iconic lake district hubs of San Carlos de Bariloche and San Martín de los Andes.
Cuyo: Stone, Meltwater, and Wine Culture
Rolling into Mendoza, San Juan, and La Rioja provinces, the plateau gives way to the Andean foothills and arid valleys dominated by world-class viticulture. Here, pure meltwater rushing down from the peaks transforms the harsh desert into internationally renowned agricultural oases.
The road sweeps past the alien volcanic fields of La Payunia and the Witches’ Cave in Malargüe, the Agua del Toro dam, San Rafael, and the prestigious Uco Valley wine region. Route 40 acts as Cuyo’s main artery, seamlessly connecting to Talampaya National Park (La Rioja) and the neighboring Ischigualasto Provincial Park / Valley of the Moon (San Juan)—the region’s crown jewels of geology and paleontology.
The Northwest: Calchaquí Valleys, Salt Flats, and Living Tradition
In Catamarca, Tucumán, Salta, and Jujuy, the elevation skyrockets. The climate violently swings between the extreme aridity of the high mountains and the dense vegetation boxed into deep valleys, all within a vibrant setting where Andean traditions remain fiercely intact.
Route 40 snakes its way through the stunning Calchaquí Valleys, hitting Santa María, the ancient Quilmes Ruins, the high-altitude vineyards of Cafayate, and bizarre rock formations like the Quebrada de las Flechas in Angastaco. After crossing Molinos, Los Cardones National Park, and surviving the grueling climb up to the Abra del Acay, the road finally hits San Antonio de los Cobres before pushing through its final stretch across the Jujuy Puna toward the Bolivian border.
Essential Tips for Trip Logistics
To tackle Patagonia, the sweet spot is between October and April, when the mountain passes are clear of snow and ice, and the daylight hours stretch out endlessly. For the Cuyo and Northwest regions, autumn and winter are prime time, since summer rains up north can trigger flash floods and wash out the gravel stretches.
Temperature swings are brutal. Layering is non-negotiable (pack lightweight technical gear alongside heavy-duty, waterproof windbreakers). Broad-spectrum sunscreen, UV-blocking sunglasses, and heavy lip balm are absolute lifesavers against the aggressively dry mountain winds.
You’ll face stretches spanning hundreds of miles with zero services. Treat the half-tank mark as your new empty. Always carry extra drinking water (at least 5 liters per person) and stash plenty of high-energy rations to keep you fueled.
