Boulder Field 100 - 50 km Ultra Run

Race completed

50 km Distance

not publishedn/a Climbing

2.5 est Grit · Entry level

Calculated from 50 km alone — the organiser has not published an elevation profile. Read 2.5 as a floor, not a verdict.

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

What the course asks

Time limit 14 hours 16:48 min/km average. Generous. Walkable throughout for most of the field. Climbing is unpublished, so this pace is a ceiling on the effort, not a measure of it. More forgiving than 85% of 50K races. Measured against 1034 races of the same distance. Cut-off calculator →

Field size ~111 Mid-sized. Company early, well spread out by halfway.

DUV results for the 2025 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, 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	50km	111	Colin Gibbons · 04:10:41	Vicky Hautkappe · 06:06:48
2024	50km	144	Chris Lewars · 03:59:56	Amanda Wilczynski · 05:38:01
2023	50km	145	Craig Winters · 04:31:53	Justyna Wilson · 04:49:11
2022	50km	145	Chris Lewars · 04:08:01	Justyna Wilson · 04:51:36
2021	50km	169	Mark Noble · 04:39:57	Colleen Moffatt · 05:09:21
2020	50km	93	Robert Kehoe · 04:15:55	Jill Roper · 05:53:32
2019	50km	168	Eric Kosek · 04:02:47	Kathleen Cusick · 05:16:00
2018	50km	150	Dustin Malavolta · 04:36:42	Maggie Guterl · 04:57:28
2017	50km	156	Russell Kalbach · 03:52:23	Lara Miller · 05:09:05
2016	50km	151	Patrick Heine · 03:54:57	Emily Clay · 04:56:48

The field shrank 23% between 2024 (144) and 2025 (111). 26% of the 2025 field were women.

DUV results for the 2025 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

Gear for this race

Chosen for 50 km of trail.

Trail Running Shoes 50 km of trail — cushioning that is still there in the last quarter.
Race Nutrition 50 km of self-supported fuelling between aid stations.
Hydration Vests Flask capacity for 50 km, without the bounce.
Headlamps A 14 h limit puts you out there after dark.
GPS Watches Battery life first — a 50 km day outlasts most full-GPS modes.

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

Adidas

Terrex Agravic Speed Ultra

RunRepeat found the Adidas Terrex Agravic Speed Ultra to be perfect for midfoot and forefoot strikers, while iRunFar noted that the shoe feels incredibly effici…

★★★★★ 4.5

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