Ultra Running Hub Challis, ID, United States · Saturday, June 20, 2026
Fixed Distance 50K
River of No Return Endurance Run 53K
Race completed
55 km Distance
2,300 m Climbing
6.2 Grit · Hardcore
What the course asks
Climbing rate 42 m / km
Mountain. Significant climbing. Steep sections will require power hiking.
Time limit 12 hours
13:05 min/km average. Generous. Walkable throughout for most of the field. More forgiving than 61% of 50K races. Measured against 1007 races of the same distance. Cut-off calculator →
Field size ~97 Mid-sized. Company early, well spread out by halfway.
DUV results for the 2026 edition (55km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.
Typical conditions, June
Daytime high 19°C
Night low 4°C
Rainfall Mostly dry
Daylight 15 h 33 m of light
Regional 2001-2020 average for June — NASA POWER, grid elevation 2207 m. Not a forecast.
The Aid Station
Course-specific beta from the community
This is a mountain course. Poles are highly recommended for the sustained climbs.
With trail terrain, choose a shoe with moderate cushioning for optimal performance.
Gear for this race
Chosen for 55 km of trail with 2,300 m of ascent.
- Trail Running Shoes42 m of climb per kilometre — grip and rock protection before cushioning.
- Race Nutrition55 km of self-supported fuelling between aid stations.
- Hydration VestsPole attachment and chest-strap stability on steep ground.
- Trekking Poles2,300 m of ascent to walk up.
- HeadlampsA 12 h limit puts you out there after dark.
Similar races
Other 50K trail ultras, closest in distance first.