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IMTUF 100 - Idaho Mountain Trail Ultra Festival 100 Miler — 2026Idaho, United States105.7mi14,188ftSep 19

IMTUF 100 - Idaho Mountain Trail Ultra Festival 100 Miler — 2026

Idaho, United States · Race day · Sep 19, 2026 · Race site: IMTUF 100 - Idaho Mountain Trail Ultra Festival

Race almanac: 1 year of race-day weather
Plan this race
Course map, elevation profile & surface
Distance
105.7mi
Elev gain
14,188ft
Elev loss
14,193ft
High point
8,045ft
Low point
5,449ft
Effective oxygen
74–82%of sea level
Surface
57% trail
Drawing the course…

Race-day light

In the dark
43%
Sunrise
7:28am
Sunset
7:49pm
Headlamp from
62mi

For a 23:15 finish (an estimate) · starting 7:00 AM Sep 19 · headlamp mi 62–the finish. Dark means the sun below civil twilight.

Climbs

11 climbs · 13,189 ft totalbiggest first
Pick a climb to find it on the profile and the map.

Elevation gain, measured two ways

SourceGainvs lidar
Course file (GPX)14,188ft-14%
USGS lidar, 1 m16,471ftreference

They differ because a GPS file picks up noise on every wiggle and often takes its heights from a coarse terrain model, while lidar maps the ground itself to about a metre. We sampled this route every 98 ft against USGS 3DEP and counted each rise of 10 ft or more, on Oct 24, 2026. The planner still uses the course file.

Aid stations as published on the course file
Aid stationMilekm
A Chinook Campground16.526.6
A Willow Basket 119.531.4
A Diamond Ridge water27.444.1
A Upper Payette Lake 132.953.0
A Lake Fork Aid Station60.697.6
A South Crestline Aid68.5110.2
A Box Creek Aid76.1122.4
A North Crestline Aid82.0131.9
A UP290.6145.7
A The Cloochman Clock96.2154.9
A Bear Pete Water & Snackies100.6161.8

Badge colours match the markers on the map above — always confirm locations and cutoffs with the race organizer.

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Nobody from IMTUF 100 - Idaho Mountain Trail Ultra Festival 100 Miler — 2026 has checked this course yet — it’s built from what the race published. Ask them to:Email your race director

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Conditions typical race-day weather for Sep 19 at the start
Typical high
59°F
Typical low
38°F
Chance of rain
39%
2025 high
75°F

Typical = the median of 2016–2025 for Sep 19 ±3 days at the start line; a wet day has 1 mm of rain or more. Historical weather from Open-Meteo.

Race almanac 1 year of this race

Past editions

On race day it reached 59°F at the start, with a low of 41°.

YearStart °FHigh point °FRainWind
2026 Sep 1959°/41°51°/37°0.15in4mph

race-day weather from the Open-Meteo historical archive (ERA5) at the start line and the course high point (8,045 ft).

Reviews what runners who have been there say

No reviews yet — be the first to run it and tell other runners what to expect.

About this course

IMTUF 100 - Idaho Mountain Trail Ultra Festival 100 Miler — 2026 covers 105.7 mi (170.1 km) with 14,188 ft of elevation gain through Idaho, United States. That is about 134 ft per mile of climbing, and 14,193 ft of descent. The course tops out at 8,045 ft and bottoms out at 5,449 ft. The surface is 57% trail, 36% gravel and 1% paved. There are 11 aid stations on course; the longest stretch between aid is 27.7 mi. The profile has 11 sustained climbs; the biggest is the climb to Bear Pete Water & Snackies, +2,493 ft over 11.9 mi at 4.0% on average (steepest stretch 21%). Race day is September 19, 2026, starting at 7:00 AM; the sun rises at 7:28 AM and sets at 7:49 PM. Typical race-day weather at the start: a high of 59°F and a low of 38°F, with a 39% chance of a wet day. The interactive map above shows the full route with its elevation profile and aid stations, built from the course's GPS file.

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Course history

  1. Sep 3, 2026Added to the catalog
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