Boulder Field 100 - 100 km Ultra Run

Race completed

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.

40.8759° N, 75.7324° W © OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Time limit 16 hours 9:36 min/km average. Comfortable. Room to walk the climbs and stop at aid. Climbing is unpublished, so this pace is a ceiling on the effort, not a measure of it. About average for a 100K. Measured against 214 races of the same distance. Cut-off calculator →

Field size ~28 Small. Long stretches with nobody in sight.

DUV results for the 2025 edition (100km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Typical conditions, September

Daytime high 24°C

Night low 12°C

Rainfall Showers likely

Daylight 12 h 40 m of light

Regional 2001-2020 average for September — NASA POWER, grid elevation 359 m. Not a forecast.

Results history

Year	Race	Finishers	Men's winner	Women's winner
2025	100km	28	Jesse Stauffer · 10:51:50	Jessica Snyder · 12:50:38
2024	100km	25	Calvin Isch · 09:23:26	Jenn Antman · 15:09:45
2022	100km	23	Mark Torres · 11:17:59	Ellen Kasiske · 13:27:08
2021	100km	33	Matthew Corcoran · 10:31:03	Melinda Coen · 12:05:51
2020	100km	16	Jeffrey Alpert · 10:41:25	Laura Moore · 12:40:44
2019	100km	24	Kevin Scott · 10:32:20	Lauren Longfield · 13:19:03
2018	100km	23	Richard Riopel · 10:13:11	Stacia Hartung · 13:27:59
2017	100km	31	Timothy Karabin · 10:19:21	Helene Strutko · 12:56:32
2016	100km	35	Michael Daigeaun · 08:57:25	Sarah Colwell · 11:31:33

The field grew 12% between 2024 (25) and 2025 (28). 18% of the 2025 field were women.

DUV results for the 2025 edition (100km) — 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 A 16 h limit puts you out there after dark.
Accessories Chafe and blisters end more 100 km races than fitness does.

Brooks

Catamount 3

RunRepeat found the Brooks Catamount 3 to have a cozier upper that enhances the overall fit, though breathability and durability could be better. iRunFar noted…

★★★★★ 4.5

Salomon