National Route 40: route guide

Ruta 40 runs the length of mainland Argentina, hugging the Andes from the South Atlantic coast to the Bolivian border. The southern end is Punta Loyola, a small port near Río Gallegos; a 100 km gap between Cabo Vírgenes and Río Gallegos means the road does not yet reach the very tip. The northern end is La Quiaca, opposite Villazón in Bolivia.

The route passes through Patagonian steppe, lake country around Bariloche, the wine regions of Mendoza and San Juan, and the high desert of the northwest. It crosses remote, thinly populated ground for long stretches, so plan fuel, water and accommodation around the towns rather than assuming services appear when you need them.

Treat the route as four stages. In the south, the run from Punta Loyola north through Río Gallegos and El Calafate is the classic Patagonia drive, with the Perito Moreno glacier and the Chalten area as the draw. This is the windiest, most remote part: long gravel, few towns, and fuel gaps that need planning.

The lakes stage around Bariloche and San Martín de los Andes is the easiest and most scenic for a first trip, mostly paved and busy in summer. The Cuyo stage links Mendoza and San Juan through wine country, with the high Andes and Aconcagua viewpoints nearby. The northwest stage runs through Salta, Cafayate and Cachi to La Quiaca, with the Abra de Acay pass at 4,972 m — the highest point on the road and a place where altitude, not traffic, is the risk.

The route spans roughly 30 degrees of latitude, so no single season suits all of it. Patagonia is best from November to March, when days are long and the worst of the wind and cold eases; outside that window, snow and ice can close high sections and services shut down. The northwest is better from May to September, avoiding the summer heat and the worst of the altitude weather.

If you want to drive the whole route in one go, aim for the shoulder months and accept that you will hit poor conditions somewhere. Check road status before remote stages: gravel roads can be impassable after rain, and temporary gravel detours around construction can run for 20 km.

Accommodation clusters in the towns the route passes through: Río Gallegos, El Calafate, Esquel, Bariloche, San Martín de los Andes, Mendoza, San Juan, Salta and Cafayate. Book ahead in Patagonia in January and February, when domestic tourism peaks, and in Mendoza during harvest events.

Outside those towns, options thin out fast. Some stretches have only a handful of hostels, estancias or roadside lodges, and in the far south you may need to plan a night in a place with no fuel station. Camping is possible in many areas but wind and cold make it a summer-only option in Patagonia.

A 4WD or high-clearance vehicle is the safe choice for the remote gravel, though a normal car handles the paved sections and the lakes stage fine. Carry spare fuel, water, a full-size spare tyre and tools; breakdown help is far away on the southern stages. Fill up whenever you see a station in Patagonia — the next one may be out of fuel.

For the Bolivian border at La Quiaca, a Carnet de Passages is required to bring a vehicle into Bolivia. Arrange it before you leave; getting one at the border is possible but can take days of paperwork. Altitude is the other preparation point: Abra de Acay sits at 4,972 m, so allow time to acclimatise before crossing and watch for symptoms of altitude sickness.

Highway robbery is not a concern on Ruta 40 itself. The asphalt pirates that operate in Argentina work busier roads and mostly target trucks, not tourist cars.