Ruta Nacional 40 Paso de Agua Negra to Rodeo
Argentina's highest vehicle pass at 4,770 meters
The approach to Paso de Agua Negra climbs through some of Argentina’s most brutal high-altitude desert, where abandoned copper mines dot the landscape like tombstones. Starting from Rodeo, the route follows RN40 through the Iglesia Valley before branching onto secondary tracks that wind past the ruins of Mina La Mejicana, where nineteenth-century miners extracted silver until the altitude and isolation broke them. At 4,770 meters, this is one of Argentina’s highest vehicle-accessible passes, where engine performance drops to half and every breath feels stolen.
This is expert-level territory demanding high-clearance 4WD, emergency oxygen, and cold-weather gear even in summer. The route requires two full days with overnight camping at intermediate elevations to acclimatize properly. Best attempted April through November when snow doesn’t block the final approach. Carry extra fuel, water, and spare parts—the nearest mechanic is three hours away in Rodeo. What you get is raw Andean wilderness where condors ride thermals above 5,000-meter peaks and the silence is absolute.
Trail Specs
| Difficulty | Expert |
|---|---|
| Trail Type | Backcountry, High Clearance |
| Surface | Dirt, Rock |
| Features | Camping, High Altitude, Historic, Remote |
| Length (miles) | 87 mi / 140 km |
| Duration | 2-3 days |
| Max elevation (ft) | 15650 ft |
| Best season | April-November |
| Minimum vehicle | High-clearance 4WD |
| Nearest town | Rodeo, San Juan |
| Land manager | Dirección Nacional de Vialidad |
| Permit required | No |
| Cell service | None |
| Water crossings | No |
| Dispersed camping | Yes |
| Start coordinates | |
| End coordinates | |
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Location
Trail Conditions
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Frequently asked questions
What's the minimum rig I can realistically take through Paso de Agua Negra?
High-clearance 4WD is non-negotiable — think Hilux, Land Cruiser, or equivalent. A stock Wrangler with factory clearance can make it in good conditions, but you want lockers or at minimum a solid LSD because the loose rock and steep switchbacks above 4,000m punish open differentials hard.
When does Paso de Agua Negra close for winter?
The pass typically closes around late November or December and reopens around April, but exact dates vary year to year based on snowfall. Don't trust a fixed date — call the Dirección Nacional de Vialidad in San Juan before you go, especially in shoulder months.
Do I need permits or pay fees to drive this route?
No trail permit is required for the Argentine side of the route from Rodeo to the pass. If you're crossing into Chile at the Paso de Agua Negra border post, you'll need standard international vehicle documentation — title, passport, and a notarized permission letter if the vehicle isn't registered in your name.
What's the hardest section and what makes it so nasty?
The switchbacks climbing to 4,770m are the crux — loose shale, narrow ledges with steep drop-offs, and altitude that kills power in naturally aspirated engines by 20-30%. Turbodiesel rigs handle it better than gas engines. If your brakes are soft or your cooling system is marginal, you'll find out here.
Is there any fuel or water available along the 87 miles between Rodeo and the pass?
None. Zero fuel stops exist on this stretch — top off completely in Rodeo before you leave. Water sources are scarce and at altitude they require treatment; carry at minimum 10 liters per person. The route passes through mining country but active operations are not reliable resupply points.
Trail track
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