The 10 Best Ultramarathons and Trail Races in the World (2027)

1. Ultra-Trail du Mont-Blanc

The Ultra-Trail du Mont-Blanc ranks first as the world's most coveted ultramarathon, a 171 km loop around Mont Blanc with roughly 10,000 m of climbing. Entry costs about €350, but securing a spot requires collecting qualifying Running Stones at UTMB World Series races and winning a lottery. Most finishers spend 30 to 46 hours on course across two nights, with elite winning times near 19 to 20 hours.

This race is for the ultrarunner who prioritizes prestige and Alpine terrain above all else, accepting a two-to-three-season campaign for a single start. It trades away accessibility and simplicity for the ultimate challenge and atmosphere. Compared to Western States, UTMB offers more vertical gain and a more international field, but demands a far more complex qualification process. Runners who want a legendary hundred within 18 months should look to Leadville or Javelina instead.

2. Western States Endurance Run

Western States Endurance Run ranks second as the oldest 100-mile trail race in the world, run every June from Olympic Valley to Auburn, California, with an entry fee of about $525. The defining challenge is thermal: high-country snow in the first 30 miles, then canyon heat where air temperatures can top 38°C. The sub-24-hour silver buckle is the headline goal, and the Rucky Chucky river crossing near mile 78 is the iconic mid-race image.

This race suits the runner who wants a historic, point-to-point American hundred with a strong community and a clear sub-24-hour benchmark. It trades away altitude for heat, making it ideal for sea-level runners who can adapt with a 10-to-14-day heat protocol. Compared to UTMB, Western States is more accessible logistically but equally hard to enter via lottery.

3. Hardrock 100

Hardrock 100 ranks third for its sheer difficulty, looping through Colorado's San Juan Mountains with roughly 10,000 m of climbing at an average elevation above 3,350 m, topping out above 4,260 m near Handies Peak. Entry runs about $235, the cheapest marquee hundred on this list, but lottery odds are among the worst in the sport and require a qualifier from an approved hard-race list.

This race is for the mountain specialist who seeks a solitary, high-altitude problem and is willing to wait years for a lottery slot. It trades away speed and heat for relentless climbing and altitude, demanding a different training focus than Western States' canyon heat. Compared to Western States, Hardrock is slower, higher, and more technical, with a more forgiving cutoff that acknowledges the course as the true adversary.

4. Leadville Trail 100

Leadville Trail 100 ranks fourth as the best value among marquee hundreds, crossing Colorado's Rockies out and back over Hope Pass, never dropping below 9,200 ft (2,800 m), with a 30-hour cutoff. Entry runs about $315–$365, and its lottery is materially more attainable than Western States or Hardrock, offering comparable history and altitude challenge with dramatically better odds of actually toeing the line. The course peaks at 12,600 ft Hope Pass, crossed twice, making altitude the primary adversary.

This race is for the runner who wants a legendary high-altitude hundred without a multi-year lottery grind, trading away exclusivity for a realistic shot at the start line. It suits those who can train for altitude or arrive early to acclimatize, as the thin air hits hardest after the halfway point. Compared to Hardrock, Leadville is more runnable and less technical, but the 30-hour cutoff is stricter, punishing poor pacing.

5. Comrades Marathon

Comrades Marathon ranks fifth as the world's largest ultramarathon, an 87–90 km road ultra between Durban and Pietermaritzburg, alternating "up" and "down" directions each year since 1921. Entry runs roughly R1,200–R2,000 (about $65–$110) plus a qualifying marathon time, making it the most affordable race on this list. The 12-hour cutoff is enforced by a gun fired across the finish line with a race official's back turned to approaching runners, creating dramatic, widely-watched footage.

This race is for the runner who thrives on mass participation and electric atmosphere, trading away technical terrain and altitude for a fast, road-based test of endurance. It suits those who want a high-finisher-count event with a strict time limit, where running out of time is the primary failure mode. Compared to Leadville, Comrades is flatter, faster, and far cheaper, but requires a qualifying marathon and offers no lottery escape from the cutoff.

6. Marathon des Sables

Marathon des Sables ranks sixth as the ultimate self-supported stage race, a 250 km crossing of the Moroccan Sahara over about six days where runners carry their own food and gear. Temperatures can exceed 40°C, with a long stage past 80 km, and entry is roughly €3,000–€4,500 including logistics and bivouac support. The race demands complete self-sufficiency, as outside support is prohibited entirely, making it a test of both physical endurance and logistical planning.

This race is for the ultra-adventurer who wants a multi-day, self-reliant challenge, trading away the speed and community of single-day races for a grueling desert expedition. It suits those who can manage heat adaptation and carry their own supplies, with the fee covering most logistics. Compared to Badwater 135, Marathon des Sables is longer and more self-sufficient, but less brutally hot on pavement.

7. Badwater 135

Badwater 135 ranks seventh for its extreme heat challenge, covering 135 miles from Death Valley's Badwater Basin, 86 m below sea level, to the Mount Whitney portal in July. Pavement radiant heat can push past 49°C, and entry is about $1,500 with an invitation-only field vetted against an ultra résumé. The course is effectively flat with no technical climbing, but the heat is the primary adversary, demanding a 10-to-14-day heat adaptation protocol.

This race is for the elite ultrarunner who has already proven themselves in other hundreds, trading away technical terrain and altitude for an extreme thermal test. It suits those who can handle heat and have the budget for a crew of two to four people and a support vehicle, as the entry fee excludes these costs. Compared to Marathon des Sables, Badwater is shorter and faster but more brutally hot on radiating pavement.

8. Tor des Géants

Tor des Géants ranks eighth for its epic scale, a roughly 330 km single-stage mountain ultra in Italy's Aosta Valley with about 24,000 m of climbing and a 150-hour cutoff. Entry runs about €800–€900, and the course crosses more than 25 high passes, making it the longest and most vertical race on this list. The 150-hour cutoff translates to roughly 2.2 km/h average including all sleep, meaning the course, not the clock, is the adversary.

This race is for the ultra-endurance specialist who seeks a solitary, multi-day mountain problem, trading away speed and community for an unparalleled test of self-sufficiency. It suits those who can manage sleep deprivation and technical descending, as quad failure is a common DNF cause. Compared to Hardrock, Tor des Géants is far longer and more vertical, but with a more generous cutoff that allows for rest.

9. Javelina Jundred

Javelina Jundred ranks ninth as the most accessible hundred-miler on this list, a looped 100-mile desert race in Arizona's McDowell Sonoran Preserve at roughly $250–$300. It is famous for its costume-friendly festival atmosphere and its reliability as a Western States qualifier each autumn, making it a practical choice for runners building a resume. The looped format means runners pass the start/finish hub repeatedly, which makes crewing trivial and drop-outs psychologically easy.

This race is for the runner who wants a fun, low-pressure hundred with excellent crew access and a high finish rate, trading away altitude and technical terrain for a flat, fast desert course. It suits those who prefer a festival vibe and want a reliable Western States qualifier without a punishing lottery. Compared to Leadville, Javelina is cheaper, flatter, and easier to crew, but lacks the altitude challenge that builds high-country fitness.

10. UTMB World Series OCC

The UTMB World Series OCC ranks tenth as the most approachable entry into the UTMB ecosystem, a 56 km race in Chamonix with roughly 3,500 m of climbing and entry around €100–€150. It is a shorter, less demanding alternative to the 171 km UTMB, but still offers the same Alpine terrain and finish-line atmosphere in Chamonix.

This race is for the runner who wants to experience the UTMB World Series atmosphere without the 171 km commitment, trading away distance and prestige for accessibility. It suits those who are building toward a longer UTMB event and want a qualifier that is also a rehearsal for Alpine terrain. Compared to Javelina Jundred, the OCC offers more vertical gain and a more international field, but is shorter and less of a festival.

How we ranked these

Rankings weighted race difficulty (distance, vertical gain, altitude, cutoff strictness), accessibility (lottery odds, qualifier requirements), cost (entry fee plus logistics), and cultural significance (history, atmosphere, finisher prestige). Entry fees and cutoff times were verified against official race sites; lottery odds and finish rates from published race statistics and reputable endurance-sport media.

Deliberately ignored: personal runner preferences, subjective course beauty, and gear sponsorship influence. Also ignored races with unverifiable 2027 dates or entry details, and races outside the ten named in the source material. The goal was to rank on measurable, comparable factors rather than hype or anecdotal reputation.

Related questions

Which ultramarathon is easiest to get into?

Javelina Jundred and most UTMB World Series qualifiers outside Chamonix have the most accessible entry. Leadville's lottery is meaningfully better than Western States or Hardrock. Any 50 km trail race is easier still and remains a legitimate first ultra.

How long does a UTMB campaign realistically take?

Two to three seasons. You need Running Stones from indexed qualifier races first, then a lottery slot that is not guaranteed on the first attempt. Budget one qualifier season plus at least one lottery cycle before planning Chamonix travel.

Is Hardrock or Western States harder?

Hardrock, by most measures — roughly 10,000 m of climbing above an average 3,350 m elevation, versus Western States' heat-driven canyon challenge. Hardrock's 48-hour cutoff versus Western's 30 reflects that gap. Both lotteries are among the sport's toughest.

Do I need a crew for a 100-miler?

Rarely mandatory. Pacers are usually permitted after roughly halfway at US hundreds, and crews are common but optional. Alpine races often restrict crew to designated life bases, and self-supported stage races like Marathon des Sables prohibit outside support entirely.

What is the best value ultramarathon on this list?

Leadville Trail 100 offers the best value at about $315–$365 with friendlier lottery odds than Western States or Hardrock. Its altitude challenge and history are comparable, but your odds of actually getting in are dramatically better, making it the smart choice for most runners.

Which race has the most atmosphere?

Comrades and UTMB, for opposite reasons. Comrades draws tens of thousands of runners and roadside crowds that turn the day into something closer to a national holiday. UTMB concentrates its intensity into the Chamonix start and finish, with the anthem, the crowds, and the mountains doing the work.

FAQ

How do I qualify for UTMB?

You earn qualifying Running Stones by finishing UTMB-indexed races, then enter the lottery. The number of stones required varies by target distance and by year, and stones for the 171 km event are the hardest to accumulate. Check the current season's requirements on the official UTMB site, since the index and stone allocation are revised periodically.

What's the hardest part of the Leadville Trail 100?

Altitude combined with the 30-hour cutoff. The course never drops below 9,200 ft (2,800 m) and peaks at the 12,600 ft Hope Pass, crossed twice. Nausea and fatigue from thin air hit many runners hardest after the halfway point, when the second Hope Pass crossing arrives on tired legs.

Are any of these races beginner-friendly?

Javelina's looped format and companion shorter distances, plus UTMB's OCC at 56 km, are the most approachable on this list. But most of the ten assume real ultra experience. A first-timer is better served by a 50 km trail race with modest elevation gain and a generous 10-to-16-hour cutoff.

How much do entry fees typically cost?

Roughly $150 for a 50 km race to over $1,500 for multi-day stage events. Most 100-milers land between $200 and $500 — Hardrock near $235, Leadville $315–$365, Western States about $525, UTMB around €350. Travel, lodging, and crew costs usually exceed the entry fee.

What's the best way to train for a high-altitude race?

Gradual acclimatization over one to two weeks at elevation is ideal. If that is not possible, arriving three to five days out is a common compromise, since the acclimatization dip deepens after the first couple of days. Supplement with hill repeats and sustained moderate-intensity long runs at whatever elevation you have available.

Which race has the most atmosphere?

Comrades and UTMB, for opposite reasons. Comrades draws tens of thousands of runners and roadside crowds that turn the day into something closer to a national holiday. UTMB concentrates its intensity into the Chamonix start and finish, with the anthem, the crowds, and the mountains doing the work.

What is the total cost of a race like Western States?

A realistic domestic US hundred runs entry ($235–$525), travel ($300–$700), lodging for three to five nights ($400–$900), crew costs, and gear replacement. Call it $1,500–$2,500 all-in for something like Leadville or Western States. Alpine trips add international airfare and peak-season lodging, commonly $3,000–$5,000 all-in.

How much time do I need to train for a 100-miler?

A serious hundred-mile build is 20 to 24 weeks of 50 to 90 km per week with dedicated vertical work — for mountain races, 1,000 to 2,000 m of climbing weekly in the peak block. Add qualifier races, which are themselves 50 km to 100 km efforts requiring their own taper and recovery.

Sources

• https://utmb.world/
• https://www.wser.org/
• https://hardrock100.com/
• https://www.leadvilleraceseries.com/
• https://www.comrades.com/
• https://marathondessables.com/
• https://www.irunfar.com/
• https://www.badwater.com/
• https://www.trailrunnermag.com/
• https://tordesgeants.it/

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