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

Direct Answer

The most coveted ultramarathon to chase is the Ultra-Trail du Mont-Blanc (UTMB), our Best Overall: a roughly 171 km loop around Mont Blanc with about 10,000 m of climbing, an entry fee near €350, and a points-and-lottery system that makes a bib the sport's biggest prize.

For runners who want a legendary 100-miler with relative value and a strong lottery shot, the Leadville Trail 100 is the Best Value at roughly $315–$365 for one of America's most storied high-altitude races. This list is for trail and ultra runners chasing a buckle, a Western States qualifier, or a bucket-list mountain adventure.

Prices range from about $150 for 50 km races to over $1,500 for multi-day stage events. Every race below is a real, currently-run ultramarathon; they are ranked on prestige, terrain, atmosphere, and the experience of toeing the line.

1. Ultra-Trail du Mont-Blanc (UTMB) 🏆 BEST OVERALL

UTMB starts and finishes in Chamonix, France, circling Mont Blanc through France, Italy, and Switzerland over roughly 171 km with about 10,000 m of vertical gain, with most finishers taking 30–46 hours through two nights in the mountains.

Entry is around €350, but you must collect qualifying Running Stones at partner races and then win a lottery slot. Winning times sit near 19–20 hours for the elite men and women. The race climbs and descends a marathon's worth of vertical several times over, crossing high cols where weather can turn from warm sun to snow within an hour.

It ranks #1 because no trail ultra matches its scenery, depth of field, and global prestige. The midnight send-off from Chamonix, with thousands of spectators and the "Conquest of Paradise" anthem, is one of the most emotional starts in sport. This is for the experienced mountain runner who has built the qualifying points and wants the sport's marquee race.

2. Western States 100

The Western States Endurance Run is the world's oldest 100-mile trail race, run from Olympic Valley to Auburn, California, every June, with high-country snow, brutal canyon heat, and a sub-24-hour silver buckle as the headline goal.

Entry is about $525, and the lottery is famously hard; you need a qualifying race plus years of accumulated tickets to realistically get in. The June heat in the American River canyons, where temperatures can top 38°C, is the defining challenge, and the river crossing at Rucky Chucky is an iconic mid-race moment.

Choose Western States for the most prestigious 100-miler in the United States. The history, the buckle, and the deep competitive field make a finish here a career milestone.

3. Hardrock 100

The Hardrock Hundred Mile Endurance Run loops through Colorado's San Juan Mountains with about 10,000 m of climbing at an average elevation above 3,350 m, finishing with the traditional kiss of the iconic Hardrock boulder.

Entry runs about $235, but the lottery odds are among the worst in the sport and require a tough qualifier from an approved hard race. The thin air, scree fields, and the high point above Handies Peak at over 4,260 m make it arguably the hardest 100 in North America.

Pick Hardrock if you want the most brutal, high-altitude US hundred. The course is so demanding that the cutoff is a generous 48 hours, and many strong runners count simply finishing as the achievement.

4. Leadville Trail 100 💎 BEST VALUE

The Leadville Trail 100 Run crosses Colorado's Rockies out and back over Hope Pass, never dropping below 9,200 ft (2,800 m), with a 30-hour cutoff and a famous big belt buckle for sub-25-hour finishers.

Entry runs about $315–$365, and while popular, its lottery is more attainable than Western States or Hardrock. It earns Best Value because few races offer this much history and altitude challenge at a more reachable price and entry, with the double crossing of the 12,600-ft Hope Pass as its centerpiece.

Choose Leadville for a storied, high-altitude 100 with a realistic shot at getting in. "The Race Across the Sky" has a rich history and a passionate mountain-town crowd that makes the experience special.

5. Comrades Marathon

The Comrades Marathon in South Africa is an 87–90 km road ultra between Durban and Pietermaritzburg, alternating "up" and "down" directions each year since 1921, and the world's largest ultramarathon with tens of thousands of finishers.

Entry runs about R1,200–R2,000 (roughly $65–$110) plus a qualifying marathon time. The strict 12-hour cutoff, enforced by a gun fired across the finish line, and the roaring roadside crowds make it a unique mass-participation ultra unlike any trail race.

Pick Comrades for the world's biggest, most festive ultra. The singing, the tradition, and the sheer scale of the field give it an atmosphere closer to a national holiday than a footrace.

6. Marathon des Sables

The Marathon des Sables is a self-supported 250 km stage race across the Moroccan Sahara over about six days, where runners carry their own food and gear in a backpack and battle temperatures that can exceed 40°C.

Entry is roughly €3,000–€4,500 including logistics, flights, and bivouac support. It is regularly called one of the toughest footraces on earth for its heat, soft sand, blistered feet, and the mental grind of self-sufficiency, including a punishing long stage of 80+ km.

Choose Marathon des Sables for the ultimate self-supported desert adventure. Surviving the dunes with everything you need on your back is a different kind of endurance test entirely.

7. UTMB World Series Events (CCC, OCC, and beyond)

The UTMB World Series runs flagship 100 km and 100-mile events worldwide, including qualifiers in the Alps, the US, and Asia, all funneling Running Stones toward the main UTMB lottery in Chamonix.

Entry varies from about €100–€300 by event and distance. The standardized series makes it the clearest pathway to a Chamonix start line, with companion races like the CCC (101 km) and OCC (56 km) offering shorter routes on the same legendary trails.

Pick a World Series race to chase scenery and UTMB qualifying points at once. It lets you sample the Mont Blanc trails before committing to the full 171 km loop.

8. Tor des Géants

The Tor des Géants in Italy's Aosta Valley is a roughly 330 km single-stage mountain ultra with about 24,000 m of climbing, run continuously with a 150-hour cutoff across two of the region's high-altitude routes.

Entry runs about €800–€900. Sleep deprivation, with most runners grabbing only short naps at life bases, and relentless climbing over more than 25 high passes make it one of the most extreme single-stage races in existence.

Choose Tor des Géants for an ultra that pushes far beyond 100 miles. The week-long effort and the strategy of when to sleep turn it into as much a psychological challenge as a physical one.

9. Badwater 135

The Badwater 135 runs 135 miles from Death Valley's Badwater Basin, the lowest point in North America at 86 m below sea level, to the Mount Whitney portal, in July heat that can top 49°C on the pavement.

Entry is about $1,500 and invitation-only based on a tough ultra résumé that the organizers vet carefully. The non-stop heat, three mountain ranges, and the radiant warmth off the asphalt make it billed as the world's toughest foot race.

Pick Badwater for the most extreme heat-and-distance challenge in road ultrarunning. Crews spray runners with water and pace them through the night to survive the desert temperatures.

10. Javelina Jundred

The Javelina Jundred in Arizona's McDowell Sonoran Preserve is a looped 100-mile desert race famous for its costume-friendly, festival atmosphere and as a reliable Western States qualifier each autumn.

Entry runs about $250–$300. The flat, fast, runnable loops and the party vibe at the "Javelina Jeadquarters" start/finish make it a popular and approachable first 100-miler.

Choose Javelina for a friendly, fast desert hundred and a Western States ticket. The looped format means you pass the energetic hub repeatedly, which helps newcomers manage the distance.

How to Choose

• Building toward UTMB? You need Running Stones from UTMB World Series qualifiers plus a lottery slot; plan two or more years ahead.
• Chasing a buckle in the US? Western States, Hardrock, and Leadville are the marquee hundreds; Javelina is the friendliest first attempt.
• Want a mass-participation ultra? Comrades offers crowds and a festive road course rather than remote mountains.
• Prefer self-supported adventure? Marathon des Sables and other stage races test logistics and survival, not just running.
• Altitude tolerance matters: Leadville, Hardrock, and Hope Pass demand acclimatization; sea-level runners should arrive early.
• On a budget? Leadville and Javelina cost far less than Badwater ($1,500) or Marathon des Sables (€3,000+).

FAQ

How do I qualify for UTMB? You must earn Running Stones by finishing UTMB World Series qualifying races, then enter the annual lottery for a Chamonix slot. The number of stones needed and the lottery odds vary by year, so most runners spend at least one to two seasons collecting points before they can apply with a realistic chance.

What is the hardest ultramarathon in the world? There is no single answer, but Hardrock 100 (altitude and climbing), Badwater 135 (extreme heat), Tor des Géants (330 km and sleep deprivation), and Marathon des Sables (self-supported desert) are all regularly cited as the toughest, each for a different reason, from thin air to soft sand.

How long does it take to finish a 100-mile trail race? Elite runners can finish a mountain 100 in roughly 15–20 hours, while most participants take 24–32 hours and use the full cutoff window. Flatter races like Javelina are faster, while high-altitude, high-vertical races like Hardrock are far slower and have correspondingly generous cutoffs.

Do I need experience before running an ultramarathon? Yes. Most 100-mile races require a qualifying ultra (often a 50-miler or 100 km) to even enter the lottery, and the marquee races demand a strong résumé. Beginners typically progress from a 50 km to a 50-miler before attempting 100 miles, building the durability the distance requires.

Bottom Line

For the ultimate ultramarathon, UTMB is the Best Overall, combining Alpine scenery, depth of field, and global prestige, while the Leadville Trail 100 is the Best Value, offering a storied high-altitude hundred at a friendlier price and a more reachable lottery. Build your qualifiers, train for the terrain, and apply early.

Sources

• UTMB official site (utmb.world)
• Western States Endurance Run (wser.org)
• Hardrock 100 official site (hardrock100.com)
• Leadville Race Series (leadvilleraceseries.com)
• Comrades Marathon Association (comrades.com)
• Marathon des Sables official site (marathondessables.com)
• IRunFar ultrarunning coverage (irunfar.com)
• Badwater / AdventureCORPS (badwater.com)