Scenic bywayCited official sources
Sonora Pass CA-108 — the Sierra crossing most RVs should avoid
30-foot length limit, 26% grade in places, narrower than Tioga, and a real challenge even in a small rig.
Sonora Pass on CA-108 crosses the Sierra Nevada at 9,624 feet. It is the second-highest pass in California and the most technically challenging Sierra crossing. Caltrans posts a 30-foot vehicle length limit. The grade reaches 26% in places. For RV travelers, Sonora Pass is the route to avoid unless your rig is genuinely small and you are confident with steep mountain driving. Tioga Pass on CA-120, just 50 miles south, is the recommended alternative for every RV class.
Frame: a highway in California — not this route.
Elevation
9,624ft
highest point · climbs from 2,000 ft
Elevation range — drawn from this page's surveyed low and high points
At a glance
Route facts worth checking before you roll out
Conservative, source-minded numbers for planning — always confirm against current conditions and state DOT 511 before you depart.
Distance
80 mi
Sonora CA to US-395 at Bridgeport
Drive time
3–5 hr
Elevation
2,000–9,624 ft
RV compatibility
Small RV only (Class B / van)
Max length 30 ft
Best season
Late June through September. Avoid if your rig is over 30 ft.
Cell coverage. Minimal. Sonora and Bridgeport have service. Central pass section does not.
Elevation profile
Climbs from 2,000 ft at Sonora to 9,624 ft at the pass; descends to 6,500 ft at Bridgeport.
Will your rig fit?
Sonora Pass CA-108 posts a 30-foot vehicle limit. Measured against the rigs listed on PickRV, 12 of 18 sizes clear it.
- Teardrop12 ft
- A-Frame Pop13 ft
- Pop-Up Camper14 ft
- Class B Pop18 ft
- Silver-Bullet Travel Trailer19 ft
- Class B City Camper Van21 ft
- Class B Camper Van Conversion22 ft
- Luxury Class B Touring Coach24 ft
- Class C Cascade Loop25 ft
- Class C Beach Cruiser26 ft
- Class C Yellowstone Adventure27 ft
- Class C Family Motorhome28 ft
6 of our listed sizes cannot drive it — everything from the super c 4x4 adventure at 33 ft upward.
The vertical line is the posted 30-foot limit. Lengths are the ones on our own listings, not manufacturer averages — check your rig's registration before you drive it.
See rigs this sizeVehicle restrictions
- 30-foot length limit (Caltrans posted)
- Grades up to 26% — the steepest paved highway grade in California
- Tight switchbacks, narrow lane widths
- Trailers strongly discouraged
Real warnings — why we recommend the Tioga alternative
26% grades are real
Caltrans posts 26% in the steepest sections. This is steeper than San Francisco's steepest residential streets.
dangerBrake fade is the practical risk
Sustained steep descent overheats brakes. Use compression braking, not service brakes.
dangerLength limit is enforced
30-ft limit posted. Caltrans cites violators.
cautionTioga Pass is genuinely the better RV option
Just 50 miles south. Gentler grades. No length limit. Use Tioga.
info
What Caltrans + Visit Mono County doesn't tell you
Caltrans posts the 30-ft limit and 26% grade clearly but doesn't always recommend the alternative. For RV travelers, the practical answer is: don't drive Sonora Pass. Use Tioga Pass instead.
The recreational draw of Sonora Pass is the high-Sierra scenery and the historical Sonora Pass Toll Road history. For passenger vehicle and motorcycle travelers it is a stunning drive. For RVs the safer, more enjoyable alternative is Tioga Pass.
Frequently asked questions
- Is the 30-ft limit measured combined?
- Yes. RV plus tow vehicle combined. A 22-ft Class B towing a Jeep exceeds 30 ft combined and does not qualify.
- What if I'm under 30 feet?
- Still expect a challenging crossing. Brake fade is the practical risk. Use lower gears. If you can use Tioga Pass instead, do.
Authoritative sources
- Caltrans QuickMap — California road status State DOT
- America's Byways — Federal Highway Administration scenic byway program FHWA National Scenic Byways
Verify current conditions with state DOT 511 systems before departure. RV restrictions may change. Weather may close roads.
Planning an RV trip along Sonora Pass CA-108?
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