Abra del Acay, Mountain pass in Salta Province, Argentina.

Abra del Acay is a mountain pass in Salta Province that sits at about 4,960 meters (16,270 ft) elevation, making it Argentina's highest navigable point on Route 40. The road follows a narrow gravel track that winds through harsh mountain terrain.

Work on the pass road began in 1957 and it was inaugurated on 8 July 1960 after three years of construction, linking the Puna plains with the Calchaquí valleys. The route followed the layout of the old Inca road, the same one travelled by the expeditions of Diego de Almagro and Juan de Matienzo, skirting the slopes of Nevado de Acay.

At the summit stands an apacheta, a mound of stones in the Inca tradition, raised in honour of Pachamama; travellers leave offerings there and ask that misfortunes (chiknis) be kept from the road. The pass is also called "nido del viento blanco", the nest of the white wind.

Travelers should arrive with repair equipment, food, water, and a full fuel tank since services are scarce and mobile coverage is absent in the area. A drive through this region demands a capable vehicle, thorough preparation, and plenty of time.

At the summit stands an apacheta, a mound of stones in the Inca tradition, raised in honour of Pachamama. Travellers leave offerings there and ask that misfortunes (chiknis) be kept from the road and for health to continue the journey. The old sign at the pass still gives 4,895 m, while some measurements suggest 5,061 m.