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

The marquee races and how they actually differ

Ultra-Trail du Mont-Blanc starts and finishes in Chamonix, France, circling the Mont Blanc massif through France, Italy, and Switzerland. The loop measures roughly 171 km with about 10,000 m of vertical gain, and most finishers spend 30 to 46 hours on course across two nights in the mountains. Elite winning times sit near 19 to 20 hours. Entry is around €350, but the fee is the easy part — you must first collect qualifying Running Stones at UTMB World Series partner races, then win a lottery slot. The midnight-adjacent send-off from Chamonix, with thousands of spectators packed into the streets and the "Conquest of Paradise" anthem playing, is one of the most emotional starts in endurance sport.

Western States Endurance Run is the oldest 100-mile trail race in the world, run every June from Olympic Valley to Auburn, California. Entry is about $525. The defining challenge is thermal: high-country snow in the first 30 miles, then canyon heat in the American River drainages where air temperatures can top 38°C. The sub-24-hour silver buckle is the headline goal; the Rucky Chucky river crossing near mile 78 is the iconic mid-race image. The lottery is famously punishing — you need a qualifying race plus years of accumulated tickets before your odds become meaningful.

Hardrock 100 loops 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, and finishes with the traditional kiss of the Hardrock boulder. Entry runs about $235 — the cheapest marquee hundred on this list — but the lottery odds are among the worst in the sport and require a qualifier from an approved hard-race list. The 48-hour cutoff is generous by design, because thin air and scree fields make this arguably the hardest hundred in North America.

Leadville Trail 100 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 large belt buckle for sub-25-hour finishers. Entry runs about $315–$365. Its lottery is materially more attainable than Western States or Hardrock, which is exactly why it earns the value slot: comparable history, comparable altitude challenge, dramatically better odds of actually toeing the line.

Beyond the trail hundreds, three races broaden the definition of what an ultra is. 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 it is the world's largest ultramarathon by finisher count. Entry runs roughly R1,200–R2,000 (about $65–$110) plus a qualifying marathon time. The 12-hour cutoff is enforced by a gun fired across the finish line with a race official's back turned to the approaching runners — a piece of theater that has produced some of the sport's most-watched footage. 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 and face temperatures that can exceed 40°C, with a long stage past 80 km. Entry is roughly €3,000–€4,500 including logistics and bivouac support. Badwater 135 covers 135 miles from Death Valley's Badwater Basin, 86 m below sea level, to the Mount Whitney portal in July, when pavement radiant heat can push past 49°C. Entry is about $1,500 and the field is invitation-only, vetted against an ultra résumé.

Two more fill out the ten. Tor des Géants in Italy's Aosta Valley is a roughly 330 km single-stage mountain ultra with about 24,000 m of climbing and a 150-hour cutoff, crossing more than 25 high passes; entry runs about €800–€900 and the real variable is when you choose to sleep. Javelina Jundred in Arizona's McDowell Sonoran Preserve is a looped 100-mile desert race at roughly $250–$300, famous for its costume-friendly festival atmosphere and its reliability as a Western States qualifier each autumn. The UTMB World Series itself — CCC at 101 km, OCC at 56 km, plus qualifiers across the Alps, the US, and Asia at roughly €100–€300 — functions less as a single race than as the entry ramp to Chamonix.

How to decide between them

The decision is not "which race is best" but "which constraint binds first." Four constraints dominate, and they rarely bind in the same order for two different runners.

Access. If you want to run UTMB in a specific calendar year, you have already lost — the Running Stones requirement plus the lottery means a realistic UTMB plan spans two to three seasons. Same for Hardrock, where multi-year lottery ticket accumulation is the norm rather than the exception. If your constraint is "I want to run a legendary hundred within 18 months," the honest shortlist is Leadville, Javelina, and the non-flagship UTMB World Series events.

Terrain tolerance. Altitude and heat are separate physiological problems with separate preparation timelines. Leadville, Hardrock, and Hope Pass demand acclimatization; a sea-level runner who arrives two days early will feel it above 11,000 ft. Western States, Badwater, and Marathon des Sables demand heat adaptation, which responds faster — a sauna or overdressed-run protocol over 10 to 14 days produces measurable plasma-volume change. Pick the stressor you can actually train for where you live.

Budget, all-in. Entry fee is the smallest line item on most of these. Leadville at $340 plus a Colorado flight, a rental car, and a crew's lodging lands very differently than Marathon des Sables at €3,500 where the fee already absorbs the logistics. Badwater's $1,500 entry excludes a crew of two to four people, a support vehicle, and a week in one of the hottest places on earth.

What you actually want from the day. Comrades and Javelina are social events with a race attached. Tor des Géants and Hardrock are solitary problems you solve mostly alone. Neither is better; they scratch different itches, and runners who choose the wrong category tend to DNF for reasons that have nothing to do with fitness.

Concrete numbers behind each option

Put the ten side by side and the spread is wider than most runners expect. Distance runs from 56 km (OCC) to 330 km (Tor des Géants) — a factor of nearly six. Vertical gain runs from effectively flat (Badwater's 135 miles of road, with three mountain ranges but no technical climbing) to 24,000 m at Tor des Géants. Entry fees span roughly $65 at Comrades to €4,500 at Marathon des Sables, a 50x range for events that all get filed under "ultramarathon."

Cutoffs tell you more about intended difficulty than distance does. Comrades allows 12 hours for 90 km — aggressive, and thousands miss it annually. Western States allows 30 hours for 100 miles. Leadville allows 30 hours for the same distance at far higher altitude. Hardrock allows 48 hours for 100 miles, which sounds luxurious until you account for 10,000 m of climbing above 3,350 m. Tor des Géants allows 150 hours for 330 km, roughly 2.2 km/h average including all sleep. A cutoff that generous is the organizer telling you the course, not the clock, is the adversary.

Finish rates follow the same logic. Mass-participation road ultras with strict cutoffs produce high absolute finisher counts and meaningful cut-off attrition. Remote high-altitude trail hundreds produce small fields where DNF often comes from weather, altitude sickness, or gastrointestinal failure rather than the clock. When you compare races, compare the *failure mode* — running out of time and running out of stomach demand entirely different race plans.

Budget the full picture. 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. An Alpine trip for UTMB or CCC adds international airfare and Chamonix-area lodging in peak season — commonly $3,000–$5,000 all-in. Marathon des Sables at €3,000–€4,500 is the outlier that looks expensive but is nearly all-inclusive; back the flights and support out of a comparable self-organized desert expedition and the premium shrinks. Badwater's $1,500 entry is genuinely just the entry.

Time is the cost nobody prices. 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. The genuine annual cost of a UTMB campaign is one qualifier season plus one target season, not one entry fee.

There is a real parallel to how operators evaluate revenue investments: the sticker price is rarely the binding number, the time-to-payback is, and the option with the worst headline cost frequently has the shortest path to a result. Runners who budget only the entry fee are doing the same arithmetic badly.

Building the campaign, in sequence

The mistake that costs the most seasons is treating race entry as step one. It is closer to step five.

Season minus two: build the qualifier base. If UTMB is the goal, identify which World Series events award the Running Stones you need for the 171 km lottery, and pick ones you can realistically finish. A 100 km World Series event is both a qualifier and a rehearsal for Alpine terrain. For Western States, run an approved qualifier and accept that your first lottery entry is a ticket-buying exercise, not a realistic shot. For Hardrock, complete an approved hard qualifier — the list is short and the races on it are serious.

Season minus one: run a hundred you can actually get into. This is the argument for Javelina and Leadville beyond price. Javelina's looped desert format means you pass the start/finish hub repeatedly, which makes crewing trivial and drop-outs psychologically easy — useful for learning what breaks in you at mile 60 without a remote-mountain penalty for finding out. Leadville teaches altitude. Between them you learn the two variables that decide Alpine and high-country hundreds.

Six months out: match your training terrain to the specific stressor. Altitude requires either living high or arriving early — most experienced runners arrive three to five days out (before the second-day acclimatization dip deepens) or commit to 10 to 14 days. Heat responds to a 10-to-14-day adaptation block ending a few days before the race. Technical descending — the thing that actually ends Alpine races via quad failure — requires downhill-specific volume that treadmills cannot replicate. If you live somewhere flat, stairwells and repeated short descents beat nothing, but plan an away-camp block.

Race month: sequence the logistics, not just the run. Pacers are typically permitted after roughly the halfway point at US hundreds; crews are common but almost never mandatory. Confirm the specific race's rules, because Alpine events often restrict crew access to designated life bases only, and self-supported stage races ban outside support entirely. Drop-bag planning at a looped race is a different problem than at a point-to-point.

Two adjacent categories are worth knowing about, because they feed the same runner pool and often serve as better intermediate steps. Obstacle course racing and multi-sport adventure racing both build the specific tolerance for moving badly for a long time under load — the skill that separates finishers from DNFs at Tor des Géants far more than raw aerobic capacity does. Runners who cross-pollinate between these disciplines usually arrive at their first hundred with better problem-solving under fatigue than pure road converts.

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.

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.

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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