Races
TERREX Lake Sonoma 100k
Lake Sonoma, California. TERREX hundred k. Ten thousand five hundred feet. Wine country heat.
62 mi19 hours220 ft to 1,335 fttech 5/106 stationsLake Sonomawine countryWSER qualifierApril
Distance62 mi
Altitude220 ft to 1,335 ft
Technicality5/10
Air45°F to 90°F
- Start220 ft
- High1,334 ft
- Low220 ft
- Finish220 ft
- California at mile 0.0
- TERREX Lake Sonoma 100k mile 12 at mile 12, cutoff 3.8000000000000003 hours
- TERREX Lake Sonoma 100k mile 25 at mile 25, cutoff 7.6000000000000005 hours
- TERREX Lake Sonoma 100k mile 37 at mile 37, cutoff 11.4 hours
- TERREX Lake Sonoma 100k mile 50 at mile 50, cutoff 15.200000000000001 hours
- Finish California at mile 62, cutoff 19 hours
Field, 2026 · 6-year sampleresults
Starters140
Finish rate69%
Median15:50
Sub-2497
Geometrycourse math
Steepest drop650 ft-6.6% over 1.9 mi
Night miles16 misunset near 19:00 local
Course records
Men8:36:09Ryan Sullivan
Women10:13:24Fiona Pascall
The cruxLake Sonoma dam climb in April heat (near mile 40)
Course DNA
The Course
TERREX Lake Sonoma 100k runs 100 km through California. Surfaces skew 80% trail / 20% dirt road. Lake Sonoma dam climb in April heat. High point near 1,335 ft. Low near 220 ft. April temps run 45°F to 90°F. The course rewards patience early and punishes rushed descents after mile 31.
The Work
Train for the climbing across 100 km. Back-to-back long runs on trail. Practice power-hiking grades above 15 percent. 19 hours total means limited margin: rehearse fueling every 45 to 60 minutes and downhill eccentric work weekly. Technicality 5/10. Build a block that simulates the crux near mile 40.
Kit
April in California: plan for 45°F to 90°F. Mandatory shell if rain is in forecast. Headlamp with spare batteries if 19 hours pushes past dark. Poles help on sustained climbs above mile 16. Vest capacity for 2 liters minimum. Shoes matched to 80% trail: lugs for mud, rock plate if the course turns technical after mile 31.
Race Day
Hold effort through mile 16. The field often splits on the first big climb after mile 31. Lake Sonoma dam climb in April heat near mile 40 is where time is won or lost. Walk the steep pinches. Run the flats and gentle downhills. Crew at major aids: socks, calories, ice if hot. Transitions under 5 minutes when possible. Final third is 21 miles of fatigue management. Finish with reserve for the last descent.
Results
TERREX Lake Sonoma 100k finish lines.
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Sources (1)
- Field stats (2026): https://ultrasignup.com/results_event.aspx?did=131180