A relentless wine country singletrack odyssey and Western States qualifier
Other trail races within 109 miles
The TERREX Lake Sonoma 100k charges through 15,000 feet of elevation gain on 95% singletrack through California wine country, opening with a sunrise summit climb to Pritchett Peak before looping the classic Lake Sonoma out-and-back. Renowned for its relentless rolling terrain through madrone groves, lakeside trails, and creek crossings, this Western States qualifier draws one of the most competitive ultra fields in North America. Eight full aid stations and five water stops support runners through a remote reservoir environment with spotty cell service and long stretches between crew access points.
Experienced ultrarunners
Geyserville, CA, United StatesApril 10, 2027
Lake Sonoma 100K is an out-and-back trail race in Geyserville, CA, United States, held on April 10, 2027. The course covers 62.1 miles, climbs 15,000 ft, and has a 19h cutoff.
| Location | Mile | Elevation | Cutoff | Crew | Drop bags |
|---|---|---|---|---|---|
Start Start | 0.0 | 230 ft | — | ||
Pritchett Peak Aid Station | 5.8 | 1,713 ft | — | ||
Woodridge Aid Station | 11.4 | 240 ft | — | Drop Bags | |
South Lake Aid Station | 12.7 | 807 ft | — | Crew | |
Island View Aid Station | 17.3 | 515 ft | — | ||
Warm Springs Aid Station | 24.2 | 499 ft | 7h30m12:30 PM | CrewHike in | Drop Bags |
Wulfow Aid Station | 29.6 | 787 ft | — | ||
Liberty Glen Aid Station | 32.3 | 1,093 ft | — | Crew | Drop Bags |
Lone Rock Aid Station | 36.6 | 1,155 ft | 11h15m4:15 PM | ||
Liberty Glen Aid Station | 40.9 | 1,047 ft | — | Crew | Drop Bags |
Wulfow Aid Station | 43.6 | 705 ft | — | ||
Warm Springs Aid Station | 49.0 | 607 ft | 15h8:00 PM | CrewHike in | Drop Bags |
Island View Aid Station | 55.9 | 515 ft | 17h10:00 PM | ||
South Lake Aid Station | 60.5 | 230 ft | — | ||
Finish Finish | 62.1 | 226 ft | 19h12:00 AM +1 |
Sign in for race-day weather at every station, points of interest, segment-by-segment analysis, pacing, and to save this race to your calendar.
Vehicle and tent camping permitted Friday and Saturday nights right next to the start/finish at the Lake Sonoma Visitor Center. No reservation required. Cars and Sprinter-style vans only in the lot — no trailers, tow-behinds, or pop-outs. Tent camping in designated areas only. Quiet hours 9pm–4am.
April temperatures in the Dry Creek Valley can reach 75–85°F; exposed lakeside sections offer limited shade in afternoon hours.
Spring conditions can include cold foggy mornings and rapid afternoon warming — dress in layers for the 5am start.
No required gear specified
No recommended gear specified
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