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Ultramarathon Runners, Take Note. These Are the World's Toughest Races.

Can your legs handle the most brutal events around the globe?

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What makes a race “tough?” For starters, if you wince while reading the race description, that’s a strong indication that you’ll need months of training to complete the route ahead of you.

A good, hard race includes several things: steep ascents and descents, unforgiving temperatures, intense terrain, and unimaginable distances. Throw in crazy-tough cutoff times, lots of fuel over long periods of time, and the mental fatigue that comes with being on your feet for that long, and some races are just all-out brutal.

Races with weird or cool quirks give them an extra edge, like if it is entirely self-sufficient from start to finish or it goes on for days like the (checks math...) Self-Transcendence 3,100 Mile event!

Runners enjoy putting their bodies and minds to the test—it’s in our blood. But only the most dedicated and ambitious athletes will set out to complete these famed endurance monsters. Take a look at what we consider some of the hardest, toughest races on the planet. (Order is based on scheduled race date, not necessarily by how difficult each race is.)

Want to tackle a tough race? Subscribe to Runner’s World+ for training advice that will help you get to the finish line.

Hardrock 100-Mile Endurance Run

hardest races in the world
Daniel Petty//Getty Images

Where: Silverton, Colorado
When: July 15, 2022

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Runners have 48 hours to complete this bad boy: 100.5 tough miles that go through roads and dirt trails along the San Juan Mountains. Participants climb around 33,000 feet and and descend another 33,000 feet, and the highest point is over 14,000 feet on Handies Peak. Every year, the course changes direction, and you’re not a finisher until you kiss the infamous “Hardrock” at the end. Oh, and be careful: the course is so harsh that even elite runners fall, get lost, or dislocate their shoulders.

Related: [The Best Trail Running Gear Right Now]

Eastern States 100

hardest races in the world
Tania Lezack

Where: Pennsylvania Wilds
When: August 13–14, 2022

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What some people may not know is that the notorious Western States has a twin. Taking place in the Pennsylvania Wilds, the Eastern States 100 takes runners through classic east coast landscape. The 102.9-mile course starts and ends at Little Pine State Park and takes racers through some super technical terrain.

Ultra Trail du Mont Blanc

hardest races in the world
Pascal Tournaire

Where: Chamonix, France
When: August 22–28, 2022

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It’s not every day you get to run through three countries. The Ultra Tail du Mont Blanc is a 106-mile loop that starts at Chamonix, France. Hitting 10,000 feet of elevation several times along the way, participants will circle around the intersection of France, Italy, and Switzerland. Needless to say, the views are pretty fantastic. But don’t let the scenery fool you—runners spend a lot of time on the mountains instead of enjoying them from the bottom. There are other events within the UTMB, but this mountain race is the cream of the crop.

Related: [Death Cab For Cutie’s Frontman is a Hardcore Ultramarathon Runner]

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Self-Transcendence 3,100 Mile

hardest races in the world
Jowan Gauthier

Where: Queens, New York
When: September 4–October 25, 2022

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If you want to torture your body while simultaneously seeing sweeping views, the Self-Transcendence race is not it. As the longest certified road race (and possibly the most miserable, mentally), this ultra historically starts at 6 a.m. one summer morning in Queens. From then until midnight every day for 52 days, participants run the same route (an average of 59.6 miles per day) for 52 days. The race originated in 1997 and has been enticing runners ever since. Why? We have no idea.

Dragon’s Back Race

hardest races in the world
Guillem Casanova

Where: Wales
When: September 5-10, 2022

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There are lots of mountain races out there, but this one has its participants running for five days across Wales—not to mention over 50,000 total feet of ascent. Competition is tight for this off-the-beaten-path, trackless mountain race. Runners can look forward to a total of more than 200 miles. While this quest sounds painful, runners can also expect incredible scenery, with a bonus of a few ancient castles along the way.

Related: [For the Second Time Ever, Runner Completes Quad-Quad Dipsea]

Tor des Geants

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Where: Aosta Valley, Italy
When: September 12–17, 2022

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There’s a saying these days that 200 miles is the new 100, and Tor des Geants is one of the O.G.’s of going double the distance—the name literally means “Tour of the Giants” in Italian. Runners face not only 205 miles, but almost every type of weather imaginable as well as enough elevation gain to climb Everest two and a half times.

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The Plain 100

Where: Plain, Washington
When: September 17, 2022

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This 100-mile, self-sufficient race sounds like it’s name: plain. Created in 1997 as an ode to the beautiful remote trails woven through Plain, Washington, this race is a fight between the runner and the road. You have 36 hours to finish (only 50 percent do, according the website) and there are no course markings, aid stations or pacers. So don’t get lost: if you do, you’re on your own.

Related: [Dean Karnazes on the Life-Changing, Soul-Searching Magic of Ultramarathons]

Pikes Peak Ascent & Marathon

hardest races in the world
Pikes Peak Marathon

Where: Manitou Springs, Colorado
When: September 17–18, 2022

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In the words of Runner’s World Runner-in-Chief, Jeff Dengate, who has completed the Ascent, “Pikes is nuts.” Unfortunately, the climb to the top is only half the battle for marathoners. Runners start at 6,300 feet of elevation and navigate a winding, narrow trail of gravel, rocks, and dirt on their way up to the summit of Pikes Peak at 14,115 feet, then make the hellish descent. In years past, there has been fresh snow on the peak, which means runners have to prepare for 60 to 70 degree weather at the base and around 30-degree temperatures at the top. To make things even more interesting, there have been lightning strikes. If you’re not careful, you (or at least your shoes) could get fried.

Spartathlon

Where: Athens, Greece

When: September 30–October 1, 2022

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For all the history nerds out there, the Spartathlon is for you. The race is what it sounds like: the route that Pheidippides was said to have run from Athens to Sparta—150-plus miles. Besides feeling like a Greek titan, runners will enjoy some perks like muddy terrain, crossing vineyards and olive groves, and ascending and descending the near 4,000-foot Mount Parthenon at night.

Related: [Have You Been Running Hilly Races All Wrong?]

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Moab 240

Where: Moab, Utah

When: October 7–11, 2022

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This event covers nearly 240 miles through Arches National Parks, and runners can only spend 112 hours in its beauty before it’s considered a DNF.

La Diagonale des Fous

Where: Réunion island

When: October 20–23, 2022

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The name of this race roughly translates to “the fool’s diagonal.” Why? Because it crosses an entire island. Réunion is to the east of Madagascar in the Indian Ocean. Participants have 66 hours to complete the course, which covers over 102 miles of distance and over 30,000 feet of elevation.

If that’s too much for you, there are two shorter races and a four-person relay the same week—all part of the greater Grand Raid weekend.

6633 Arctic Ultra

hardest races in the world
W.Murray

Where: Yukon Territory, Canada
When: February 23, 2023

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If you’ve ever wanted to feel like you’ve reached the end of the world, this race is your ticket. The 6633 Ultra offers 120-mile and 380-mile races that start in Canada’s Yukon Territory and continue through the Northwest Territories. Get ready for a lot (and we mean a lot) of heavy winds and temperatures ranging from 9-30 degrees, but you can also look forward to beautiful panoramic views. Oh, and if you choose the 380-mile course (ouch), you’ll end your race at the hamlet of Tuktoyaktuk along the banks of the Arctic Circle. Now that’s an epic finish line.

Related: [Best Winter Running Shoes]

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HURT 100 Trail Run

Where: Honolulu, Hawaii
When: January 23, 2023

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Hosted by the Hawaiian Ultra Running Team (HURT), this race is what its acronym spells: hurt and pain for 100 miles. Racers have 36 hours to complete the course, which is 99 percent singletrack trails. The looped course has five laps of roots, puddles, rocks, and other treats through a semi-tropical rain forest. There are also 20—count them, 20—stream crossings, for an added bonus.

Iditarod Trail Invitational

hardest races in the world
Anchorage Daily News/Getty Images

Where: Knik, Alaska
When: February 26, 2023

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To add some chill to our race catalog, we thought a good Alaskan snow race would do the trick. In this annual invitational, participants literally run, fat bike, or ski the 1,000 mile Iditarod course. Since the inaugural year of 2000, only a few dozen individuals have finished the race to Nome. In order to even attempt the 1,000-mile race, you’ll have to complete the 350-mile version of the event that finishes in the village of McGrath.

Related: [Ten Days, 350 Miles, and Countless Moose Encounters: What It’s Like Running the Iditarod]

The Barkley Marathons

barkley marathons
Brian Dalek

Where: Wartburg, Tennessee
When: Early April, 2023
Register: Find your way in

Welcome to five loops of death—if you’re strong enough to make it that far. Deep in the backcountry of Tennessee lies a 100-plus mile course (likely longer) created to break anyone who attempts it. Some “highlights” include: a conch shell in the middle of the night that alerts you to the start, 120,000 estimated feet of climbing and descent if you do the whole thing, and nice views of the valley while simultaneously being pierced by briars. One loop basically equals a marathon distance (or more), and runners must complete the loop five times in under 60 hours to be crowned a finisher. In more than 30 years, there have only been a handful of individuals who have completed it (and no one finished in 2019). If you’re supposed to race the Barkley, you’ll find a way to enter. (To learn more about it, listen to our Human Race podcast.)

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The Foot Levelers Blue Ridge Marathon

hardest races in the world
Kemper Mills Fant

Where: Roanoke, Virginia
When: April 22, 2023

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In terms of southeastern marathons, the Blue Ridge is known to be one of the hardest road marathons in the U.S. because you are either constantly climbing or dropping. Its course begins and ends in downtown Roanoke and runs along the Blue Ridge Parkway, one of the most picturesque drives in the south. Runners start up Mill Mountain and then progress to perhaps the most challenging part: ascending Roanoke Mountain, just more than 2,000 feet. After reaching the top, participants take a deep descent. They experience a total 7,430 feet in elevation change during the entire race.

Related: [What Exactly Is an FKT?]

Marathon des Sables

hardest races in the world
Marathon des Sables

Where: Sahara Desert, Morocco
When: April 21–May 1, 2023

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Smack in the middle of the Sahara Desert is one of the most demanding and scorching running routes in the world. The race’s total distance is 150 to 156 miles, adjusting year after year. Runners split up the course over six days and only have one day to rest, which is usually after the longest stretch. Who’s crazy enough to run 156 miles through the Sahara? Founder Patrick Bauer walked 217 miles through the desert, only supported by what was on his back. He turned it into a race in 1986 and it remains one of the most popular ultras in the world.

Everest Marathon

Where: Mount Everest base camp
When: May 29, 2023

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As if climbing Mount Everest wasn’t hard enough, someone thought running a marathon around it was a good idea. Participants are required to be in Nepal for three weeks prior to the race to get acclimated to the altitude. They will get a tour of Kathmandu and a trek to Kala Patthar for some epic views—so the vacation makes up for the few hours of hell. The 26.2-mile race starts at the Everest Expedition Base Camp at almost 18,000 feet and finishes at Namche Bazaar at 11,306 feet. (Top runners are lucky to crack 4 hours.) The route is pretty much all downhill with two steep uphill sections. And it’s very, very cold, so pack accordingly.

Related: [Here’s Why Kilian Jornet Wanted to Scale Mount Everest Twice in One Week]

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Western States 100-Mile Endurance Run

hardest races in the world
Luis Escobar

Where: Squaw Valley, California
When: June 24-25, 2023

Register

If you know at least one name of an ultra race, chances are it’s Western States. It’s officially the oldest 100-miler in the world and brings people from all over to master the infamous, hot course. Runners have 30 hours to conquer the west coast beast, and over time will climb more than 18,000 cumulative feet in elevation and descend more than 23,000 feet. At some points, runners are so high in elevation that they have to run through snow, and other times they are completely exposed in the summer heat.

Badwater 135

hardest races in the world
Chris Kostman/Badwater.com © Adventure CORPS

Where: Death Valley, California
When: July 4-6, 2023

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If you’ve ever wanted to know what it feels like to run the lowest valleys and highest peaks in the U.S., the Badwater 135-mile race is what you need. The course starts at Badwater Basin in Death Valley, the lowest elevation in North America, and finishes at the end of the road on Mount Whitney, the tallest mountain in the continental U.S. The race covers three mountain ranges and participants experience 14,600 feet of cumulative ascent and more than 6,000 feet of cumulative descent.

Related: [Looking Back at Badwater, 30 Years Later]

Headshot of McGee Nall
McGee Nall
Contributing Writer

After a summer internship with Runner’s World in 2017, McGee has somehow convinced the team to let her keep writing for them as a freelancer. Her work for both Runner’s World and Bicycling consists mostly of news and human interest pieces. Her favorite stories to tell are ones of “ordinary” people doing extraordinary things through running and cycling, whether accomplishing personal goals, overcoming severe trials, or transforming their communities. Her writing has also appeared on ACTIVE and Paste Magazine. When she’s not running or eating, you can probably find her still eating. 

Headshot of Gabrielle Hondorp

Before joining Runner's World, Gabrielle Hondorp spent 6 years in running retail (she has tested top gear from shoes, to watches, to rain jackets which has expanded her expertise—and her closets); she specializes in health and wellness, and is an expert on running gear from head-to-toe. Gabi began her journalism career as a Digital Editorial Fellow for Runner’s World and Bicycling Magazine, and has since advanced to a Runner's World Editor specializing in commerce. She has a double degree in English and Media and Communication from Muhlenberg College where she also ran cross country and track. 

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