Colfax Highway Climb

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: no bike crashes were reported along the climb from 2021–2025.

How long and steep is the Colfax Highway climb?

2.9 miles (4.7 km) at 3.5% on average, climbing 531 ft (162 m) from 2,398 ft to 2,930 ft. The steepest half kilometre averages 6%. That makes it a Category 3 climb.

Where does the climb start and finish?

It starts at 39.21626, -121.05991, where Colfax Highway leaves Colfax Avenue, and tops out on the road at 39.19933, -121.01707.

Is Colfax Highway 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.

• Idaho Maryland RoadCat 3 · 4.5 mi at 3.9% · 932 ft · starts 0.7 mi away
• Deer Park DriveCat 3 · 1.2 mi at 8.8% · 558 ft · starts 2.3 mi away
• Gracie RoadCat 3 · 1.6 mi at 7.2% · 591 ft · starts 3.7 mi away
• Banner Mountain TrailCat 3 · 2.5 mi at 4.2% · 551 ft · starts 3.8 mi away
• Red Dog Road from Boulder StreetCat 3 · 3.8 mi at 5% · 1,007 ft · starts 4.3 mi away
• Willow Valley RoadCat 2 · 3.1 mi at 6.7% · 1,109 ft · starts 4.8 mi away
• Rattlesnake RoadCat 3 · 3.2 mi at 3.3% · 558 ft · starts 4.8 mi away
• North Ponderosa WayCat 3 · 2.1 mi at 5% · 568 ft · starts 4.8 mi away