Marinwood, CA, United States · Saturday, March 20, 2027

Fixed Distance 100K

The Big Alta

171 days away

100 km Distance

not publishedn/a Climbing

5.0 est Grit · Challenging

Calculated from 100 km alone — the organiser has not published an elevation profile. Read 5.0 as a floor, not a verdict.

38.0360° N, 122.5656° W © OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Field size ~196 Mid-sized. Company early, well spread out by halfway.

DUV results for the 2026 edition (50km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Typical conditions, March

Daytime high 15°C

Night low 7°C

Rainfall Mostly dry

Daylight 12 h 06 m of light

Regional 2001-2020 average for March — NASA POWER, grid elevation 87 m. Not a forecast.

Results history

Year	Race	Finishers	Men's winner	Women's winner
2026	50km	196	David Norris · 03:43:07	Klaire Rhodes · 04:12:41
2025	50km	225	Eli Hemming · 03:19:30	Tabor Hemming · 04:04:58
2024	50km	197	Eli Hemming · 03:38:33	Lotti Brinks · 04:42:57

The field shrank 13% between 2025 (225) and 2026 (196). 42% of the 2026 field were women.

DUV results for the 2026 edition (50km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

The Aid Station

Course-specific beta from the community

👟 gear

With trail terrain, choose a shoe with moderate cushioning for optimal performance.

By UltraHub Expert

🥤 nutrition

For 100km+ efforts, prioritize real food at aid stations to prevent palate fatigue.

By UltraHub Expert

Gear for this race

Chosen for 100 km of trail.

Trail Running Shoes 100 km of trail — cushioning that is still there in the last quarter.
Race Nutrition Past 100 km the palate quits before the legs do — carry more than one flavour.
Hydration Vests Flask capacity for 100 km, without the bounce.
Headlamps 100 km almost certainly means running into the night.
Accessories Chafe and blisters end more 100 km races than fitness does.