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Ultras · US · ID

IMTUF 100 - Idaho Mountain Trail Ultra Festival

15th Annual IMTUF100
IMTUF 20 Mile · 20M
Waitlist only
As of late Aug 2026 (about 3-4 weeks before race day): the 100 Mile shows 203 registered entrants on UltraSignup against the RD's stated field cap of 200, with an active 76-person waitlist. The 20 Mile shows 38 of its 75-entrant cap and no waitlist (still open). Neither race has run yet for 2026.
Race dateSeptember 20, 2026
Start9:00am
Whenin 29 days
First held2012
Free, and always will be. NavRun makes money from race-day planning for runners who want it, never from this. Ultras change constantly, sometimes the morning of. Always confirm with the race director and the official website before you rely on anything here.
Distance 20M
Climb not checked yet
Descent not checked yet
High point not checked yet
Time limit 9:00:00
Aid stations 4
Started not checked yet
Finished not checked yet
Finish rate not checked yet
The course

Where it goes loop · 4 aid stations · rust marks a stop your crew can reach

No official GPX on file yet. These are the aid station coordinates, not the trail. Have the GPX? Send us the link.

A 20+ mile loop from Jug Mountain Ranch sharing the 100 Mile's opening climb over Ladybug and Jughandle Mountains and down the talus to Louie Lake (the first ~11 miles), then right onto the Louie Lake Loop Trail up and over Twin Peaks Pass, descending to Boulder Lake, along the Boulder Lake shoreline trail and across the Boulder Lake Dam to Boulder Lake Trailhead Aid Station (with a short out-and-back to the aid station itself), then the same final miles as the 100 Mile course back to the finish at Jug Mountain Ranch.

"A tough and beautiful 20 mile mountain race. Jughandle Mountain is the towering peak southeast of McCall... defended by steep and unrelenting cross country slopes and a crown of granite talus fields." Shares the 100 Mile's mandatory WALK (no running) zone through the Jughandle talus. Self-sufficiency is emphasized: only one well-manned aid station (Boulder Lake) plus one unmanned water stop; runners are told to pack as for a long unsupported training run. Course records are not separately tracked/published for this distance in the sources checked.

The race

What this one is

A 100-mile mountain loop race starting and finishing at Jug Mountain Ranch near McCall, Idaho, crossing multiple 7,000-8,300+ ft passes in the Salmon River Mountains with roughly 22,000 ft of climbing on rugged, TUF footing. A companion 20-mile race over Jughandle Mountain (the IMTUF 20 Mile) starts the following morning from the same venue. Both races together make up the Idaho Mountain Trail Ultra Festival (IMTUF).

First run in 2012; 2026 is the 15th running. The course ran clockwise in 2012 and switched to counter-clockwise in 2013. The current 'Supercourse' routing was introduced in 2020 and has been trimmed slightly at the start/finish in most years since (most recently losing about 1.5 miles in 2025 due to logging activity in the area); the 2026 course is planned to be identical to 2025. Since 2012 the race has run with permission from the Payette National Forest McCall Ranger District and the Idaho Department of Lands.

Getting in

Getting in Entry, lottery and what the race asks of you before race day.

Lottery
No
Lottery opens
not checked yet
Lottery draw
not checked yet
Field cap
75
Registration
UltraSignup ultrasignup.com
Qualifying
not checked yet
Minimum age
not checked yet
Transfers
No imtuf100.blogspot.com
Deferrals
No imtuf100.blogspot.com
Crew, pacers and drop bags

The rules that shape your day Anything marked "not checked yet" is a gap in what we hold, never a no from the race.

Crew allowed
Yes docs.google.com
Vehicles per runner
not checked yet
Pacers
not checked yet
Muling
not checked yet
Drop bags
not checked yet
Cupless
not checked yet
Course marking
Fully Marked docs.google.com
Night running
No docs.google.com
Dogs
Not allowed imtuf100.blogspot.com
Headphones
not checked yet
Crew rules
not checked yet
Pacer rules
not checked yet
Drop bag rules
not checked yet
Cutoff philosophy
Single finish-line cutoff, no intermediate cutoffs published: "Cutoff: 6:00 PM- same as for the IMTUF100 Mile. 9 hours is plenty of time for anyone to go 20 miles." imtuf100.blogspot.com
Aid stations

Every stop, and what you get there ● yes   · no   ? nobody has checked

Mile Station Cutoff Crew Bag Pacer Med To next
0.00 Jug Mountain Ranch (Start)
4,955 ft
? ? ? ? 7.00
7.00 Unmanned water stop (Jug Meadows) ? · · ? ? 8.00
15.00 Boulder Lake Trailhead
6,234 ft
? ? ? ? ?
? Jug Mountain Ranch (Finish)
4,955 ft
6:00pm ? ? ? ?
Driving your crew

Getting your people there 1 stop with directions the race published.

Boulder Lake Trailhead mile 15.00

Same as the 100 Mile's leg 7 (Lake Fork Aid to Boulder Lake Aid Station): via Rt 55 south to Elo Rd/Farm-to-Market Rd, then LEFT on Boulder Lake Road (Forest Road 403).

docs.google.com
Same race, other lines

Other distances and other years

Other distances
IMTUF 100 Mile (100M)
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Where this came from. Every fact on this page records its source and when we last checked it: 102 sources for this race. Hover a source link to read the sentence it came from.
37% of what we track for a course is filled in. The rest says "not checked yet" rather than guessing.
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