California Fall Classic 100K and 55K

October 17th 2026
Healdsburg, CA
55 KM | 100 KM

(formerly Lake Sonoma 100K)

Come experience one of the most RELENTLESS and beautiful ultras on the West Coast, with two 'California Classic' courses that navigate miles upon miles of single track with majestic views of Lake Sonoma, nestled in the beauty of wine country during harvest season. The fall date will make the CSC100K perfect for runners who are looking for a late season challenge, prefer cooler weather, or want to have one last chance to snag a qualifier for the Western States.

The course, while relentless, will have generous cutoffs and aid stations to allow participants to complete the race. The cutoff times at the aid stations reflect the pace required to run a Western States qualification time of 18 hours (17 min/mile). For the safety of the runners there will be cutoffs enforced at Lone Rock, Little Rock, Madrone Crosscut, and Warm Springs Aid Station (details on website). There will be a total of 5 full aid stations and 3 water stations for the 100K meaning that runners will not have to go more than 7 miles between aid at any time. The 55K will have the same time as the 100K to complete the course and has a total of 5 full aid stations and 2 water stations and starts at 6 AM.

Upcoming Races

Oct 17 2026
55 KM
New course starting 2023
7,060 7,060 ft.
Single Loop
4 Elevation Rating
Very hilly, ~7500-12,500 feet in 50 miles
2 Surface Rating
Mostly groomed trail or dirt roads
Oct 17 2026
100 KM
New course starting 2023
13,848 13,848 ft.
Out and Back
4 Elevation Rating
Very hilly, ~7500-12,500 feet in 50 miles
2 Surface Rating
Mostly groomed trail or dirt roads

Results

100 KM New course starting 2023

Date Finishers Top Result (F) Top Result (M)
10/18/25 218 11:47:43 10:04:00
10/19/24 176 12:22:27 9:59:30
10/21/23 239 12:11:04 9:35:26

55 KM New course starting 2023

Date Finishers Top Result (F) Top Result (M)
10/18/25 102 5:17:44 4:21:42
10/19/24 105 5:00:48 4:23:09
10/21/23 106 5:20:25 5:19:32
Date Finishers Top Result (F) Top Result (M)
05/28/22 70 11:24:48 8:59:58
09/05/21 46 13:22:58 12:15:29
Date Finishers Top Result (F) Top Result (M)
05/28/22 58 6:05:12 6:01:59

Weekly Newsletter

A roundup of the week's content and most recent race results. Sent once a week on Thursday.

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