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R-275 · Route File

Sonora Pass

Central Sierra Nevada, California · United States

The high State Route 108 trans-Sierra crossing between Sonora and US 395 through Stanislaus National Forest and the Marine Corps mountain training area.

Primary window
Late spring - autumn after confirmed gate opening
References
9
Coverage
established
Reviewed
Jul 2026

Operational warnings

red · Operational constraint

Caltrans closes the upper State Route 108 crossing over Sonora Pass each winter and reopens it only after snow and hazards are cleared.

During the closure, State Route 108 cannot provide a trans-Sierra vehicle crossing.

Planning response: Confirm the current pass status in Caltrans QuickMap and use an open all-season crossing when closed.

Seasonal windows are planning triggers, not a substitute for current road, weather or land-access reports. Recheck the official sources below before departure.

Route tire evidence

Tires reported on Sonora Pass

No reviewed tire observation is published for this route.

Open the Tire Library

No tire name is inferred from route popularity, forum mentions or marketing. A report appears only after its tire, motorcycle, route context, date and named source are reviewed.

Route-specific references

Sources for Sonora Pass

Information tied directly to this road, track or route.

Roads and access

Specialist and community

Regional reference desk

Authorities covering the wider journey

Shared road, weather and access services used across Route Files in this region.

Weather

Roads and access

Emergency and medical

Field Links are reviewed references, not live guarantees. Conditions, closures, services and regulations change. Confirm critical information with the responsible authority before relying on it.