Sonora Pass · Hwy 108
The steep eastern climb over the Sierra crest, narrow and continuously curving with grades reported as high as 26% near the summit.
Loading map…
Closed by snow every winter, typically November through May. Confirm it is open before planning a crossing. Check current access ↗ · Reviewed 2026-09-12
Road shape
- Length
- 23.6 mi
- Bends
- 86
- Switchbacks
- 11
- Bends per mile
- 3.6
- Turning per mile
- 431°
- Curviest rank
- 63of 128
Measured from the OpenStreetMap centreline at a 20 m sampling step — road shape only, not a safety or speed judgement. How bends are counted.
Elevation
- Total climb
- 7,004ft
- Climb per mile
- 297ft
- Highest point
- 9,619ft
- Steepest grade
- 12.3%
Sampled every 100 m from USGS 10 m elevation data, a public-domain federal dataset. Total climb counts vertical change in both directions, so it does not depend on which way you drive. How elevation is measured.
Speed limits
40–55 mph
Mapped limits
Approximate guide; limits vary by section. Follow posted signs.
OpenStreetMap tags cover approximately 100% of this trace. These values have not been checked against current signs.
Posted signs always govern. How speed evidence is handled.
Sources
Difficulty 3/3 (Demanding) is our editorial rating of width, bends and sightlines; “Technical” describes character, not a target speed. Full method. Identified from:
- USDA Forest Service · Stanislaus National Forest, Highway 108 corridor ↗
- Jalopnik · Probably the steepest stretch of highway in the US ↗
- Wikipedia · Sonora Pass ↗
- OpenStreetMap road data ↗ (18 ways in this trace)
Reviewed 2026-09-12. The trace shows selected road sections, not a navigation route.