State Highway 108 Climb near Sonora
- long (24.6 km)
- 15 mi
- long (24.6 km)
- of climbing (792 m)
- 2,598 ft
- of climbing (792 m)
- average grade
- 3.2%
- average grade
- steepest 500 m
- 7.2%
- steepest 500 m
Elevation profile
From 1,293 ft at the bottom to 3,891 ft at the top. Grades are averaged over each half kilometre, from USGS elevation data, so short ramps can be steeper than they show.
Weather at the top of State Highway 108 this week
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Is it safe to bike up State Highway 108?
We don't rate roads as safe or unsafe: crash counts can't say how risky a ride is, and roads people like to ride draw more riders, so they see more crashes. What the records show: 3 bike crashes were reported on or beside State Highway 108 along the climb from 2021–2025. Of the 3 where the cyclist's direction along the climb can be read, 1 was coming down and 2 going up.
Common questions about State Highway 108
- How long and steep is the State Highway 108 near Sonora climb?
- 15 miles (24.6 km) at 3.2% on average, climbing 2,598 ft (792 m) from 1,293 ft to 3,891 ft. The steepest half kilometre averages 7.2%. That makes it a Category 1 climb.
- Where does the climb start and finish?
- It starts at 37.92184, -120.44907, and tops out on the road at 38.02881, -120.23092.
- Is State Highway 108 paved?
- Yes, by its OpenStreetMap tags.
- How is the category worked out?
- From the climb's shape only: length in metres × average grade (%) of 16,000 or more for Cat 3, 32,000 for Cat 2, 64,000 for Cat 1 and 80,000 for HC. It describes how hard the climb is, not traffic or crashes.
- Where does this data come from?
- The climb is found from OpenStreetMap roads and USGS 3DEP elevation (every climb, not a list of famous ones). Access is from OpenStreetMap tags; gates and closures change, so obey posted signs. Crash counts are police reports in the California Crash Reporting System (CCRS) on data.ca.gov, counted where their map location is within 100 ft of the climb. The forecast is from the National Weather Service.
Other climbs nearby
- Jamestown RoadCat 3 · 2.3 mi at 5% · 623 ft · starts 3.2 mi away
- Twist RoadCat 3 · 1.4 mi at 7.3% · 548 ft · starts 4.8 mi away
- Lyons Bald Mountain RoadCat 3 · 2.0 mi at 7.3% · 761 ft · starts 6.1 mi away
- Skyview DriveCat 3 · 1.0 mi at 12% · 646 ft · starts 6.5 mi away
- Mono WayCat 3 · 3.2 mi at 4% · 676 ft · starts 6.6 mi away
- Algerine-Wards Ferry RoadCat 3 · 2.2 mi at 4.8% · 558 ft · starts 6.7 mi away
- Tuolumne RoadCat 3 · 4.6 mi at 3.4% · 814 ft · starts 6.7 mi away
- Parrotts Ferry RoadCat 3 · 4.3 mi at 4.5% · 1,037 ft · starts 8.0 mi away
Found from OpenStreetMap roads and USGS 3DEP elevation; ranked on shape only. Category 1: length in metres × average grade (%) of 16,000 or more for Cat 3, 32,000 for Cat 2, 64,000 for Cat 1 and 80,000 for HC. It describes how hard the climb is, not traffic or crashes. Crashes: bike crashes reported within 100 ft of the climb, 2021–2025, from the California Crash Reporting System (CCRS), counted only where the report has map coordinates. Weather: National Weather Service. Access from OpenStreetMap tags; obey posted signs. How the data works.