UTMB — The World's Greatest Mountain Ultra

The Race Around the Mountain

UTMB — Ultra-Trail du Mont-Blanc — is the most watched, most covered, and most coveted ultramarathon in the world. It starts and ends in Chamonix, France, and loops 106 miles around the Mont Blanc massif through three countries: France, Italy, and Switzerland.

The course climbs 32,940 feet. It crosses mountain passes above 8,000 feet. It runs through medieval Italian villages at 2 a.m. and along Swiss ridgelines with views of glaciers at sunrise. It is — by any measure of scenery, difficulty, competition, and history — the most complete mountain ultra on earth.

The race has been running since 2003. It now draws tens of thousands of applicants for roughly 2,300 spots. Watching the mass start in Chamonix, with thousands of headlamps moving up into the Alps in the dark, is one of the iconic images of the endurance sports world.

The Course

UTMB starts in Chamonix’s town center and immediately heads into the mountains. The course runs clockwise around Mont Blanc — the highest peak in the Alps at 15,777 feet — traversing terrain that ranges from French alpine forest to exposed Italian ridgelines to Swiss glacial valleys.

Les Contamines (Mile 20): The first major town and crew access. Runners arrive here in the night, refuel, and push on into the Italian section.

Courmayeur, Italy (Mile 50): The midpoint and the most important checkpoint. The Italian section of the course is widely considered the most beautiful and among the most demanding. Arriving at Courmayeur in good shape means the race is open. Arriving destroyed means survival mode for 50 more miles.

Grand Col Ferret (Mile 56): The highest point of the race at 8,323 feet. The crossing into Switzerland. The wind here is among the most reliably unpleasant sections of the course.

Champex-Lac, Switzerland (Mile 68): The Swiss section is known for its gentler grades compared to the Italian mountains — which is a relative term. Nothing at UTMB is gentle. The Swiss section simply offers slightly more runnable terrain before the return to France.

The Final Return to Chamonix (Miles 90-106): The last section back into France builds through several ridge traversals before descending into the Chamonix Valley. The final run through Chamonix’s streets — lined with crowds even at 2 or 3 a.m. — is one of the most emotional finish experiences in endurance sports.

Qualification — The UTMB Index

UTMB no longer accepts first-time applicants through a simple lottery. Runners must accumulate Running Stones (formerly UTMB Index points) by completing qualifying races in the UTMB World Series. The system requires runners to have demonstrated mountain ultra performance before they are eligible to enter the lottery.

Hans Troyer’s UTMB Index: 922 — a score that places him well within the qualification range for UTMB entry and reflects his results at Black Canyon (2026 win) and Western States (2025, 8th place).

Higher index scores improve lottery odds. Elite runners with sufficiently high indices may receive direct invitations.

Cutoffs

The race has a 46-hour cutoff. Aid station cutoffs are strictly enforced — UTMB is not a race that bends its rules for compelling circumstances. The cutoff system eliminates hundreds of runners most years, particularly on the Italian section where the difficulty spikes and earlier conservative runners fall behind pace.

The Field

UTMB assembles the deepest professional field in ultrarunning every August. Every major name in the sport — Courtney Dauwalter, Kilian Jornet, Jim Walmsley, Francois D’Haene, Camille Herron — appears on the UTMB start list at some point in their career. The race is the de facto world championship of ultrarunning.

Kilian Jornet has won UTMB five times. Courtney Dauwalter holds multiple wins and course records across the UTMB family of races. The depth of the elite field means that even a 20th-place finish at UTMB represents a world-class performance.

Why UTMB Matters for American Runners

The growth of the UTMB World Series has created a direct connection between American qualifier races and the Chamonix start line. Black Canyon, Western States, and a growing number of US races now offer UTMB Index points. American ultra runners who build their résumé in the US qualifying circuit are increasingly competitive at UTMB — and UTMB increasingly shapes how American runners think about their own race calendars.

Running UTMB is the mountain ultra equivalent of running the Boston Marathon for road runners — except Boston is far easier to qualify for.

106 miles | 32,940 ft gain | Late August | Loop start/finish: Chamonix, France | Crosses France, Italy, Switzerland | Running since 2003