El Paso de Agua Negra (Black Water Pass) is an international high mountain pass, at an elevation of 4,780m above the sea level, located in the border between Argentina and Chile, linking the IV Region of Coquimbo (Chile) with the Province of San Juan (Argentina).
The surface of the road is gravel and sand, and chains or snow tyres can be required anytime.The pass connects La Serena and San José de Jachal. The distance between the major cities of both countries nearest to this pass is 505 km. 365 are paved and the rest are consolidated roads, but is driveable with any kind of vehicle.
Because of its altitude, this pass is open only in summer (from December to April). The rest of the year is blocked by snow. It is the highest border crossing between Argentina and Chile at an altitude of 4780 meters above sea level, and the traffic is low, being used by 200 vehicles every year.
Opened in 1965 , the road was closed in 1977 because political problems between the two countries and reopened to the public in 1994. Nowadays are being constructed 2 tunnels, with a total lenght of 14km, which will allow an inter-oceanic communication through this pass.