Abra del Acay

The Abra del Acay is the highest point on Argentina's RN40 and one of the highest passes reachable by ordinary road anywhere, topping out at close to 4,900 metres beneath the Nevado de Acay. The crossing links the puna town of San Antonio de los Cobres with the upper Calchaquí valley at La Poma, and it is entirely unpaved, a narrow track of loose stone that climbs in tight bends past mine workings and old refuges to a summit marked by a simple sign and, usually, a fierce wind. The reward is a view over ranks of Andean peaks and, on clear days, distant volcanoes on the Chilean border. Vehicles lose noticeable power in the thin air, and drivers are strongly advised not to attempt it alone or late in the day.

What you actually see

• The summit marker - the pass sign at close to 4,900 metres with peak views.
• The Nevado de Acay - the mountain rising above the pass to over 5,700 metres.
• The gravel climb - tight switchbacks and loose stone on the ascent.
• The Andean panorama - ranks of peaks and distant volcanoes on clear days.

When to go

April to November, and even then only in settled weather; snow closes the pass in winter and summer rain washes out the track. Cross in the morning and never attempt it in the dark. Acclimatising for a night or two at San Antonio first is sensible.

Honest expectations

This is a demanding drive: no barriers, loose surface, no services, no phone signal and severe altitude that affects both people and engines. Breakdowns here are serious. Many rental agreements exclude it. Travellers with heart or breathing conditions should avoid it entirely.

Nearby

San Antonio de los Cobres is north; La Poma and the Calchaquí valley lie south.