What are the toughest 100 milers in the World?

Following World’s top 10 toughest Ultramarathons, that was very well received by the ultrarunning critics, the following is the list of some of the world’s most challenging 100-mile races.

As mentioned in the previous blog, there can be no official list of TOP 10 or 20 Toughest 100-mile Ultramarathons in the World as each race poses a different challenge, a different threat to the physiology of the body, a different danger to life, a different landscape, a different terrain, different weather conditions and attract a different breed of runners. Some races being remote demand mandatory crew support, however, some races pose an additional challenge by asking runners to carry all their supplies from the Start. No list is perfect, just like this. And no list can be final. It’s always a working list that needs to be updated regularly as Race Directors keep tweaking the races, and new races keep showing up, challenging the challenge of existing ones. Each list offends certain community of ultrarunners, rightly so, because there is no possible perfect list. Each race is the toughest in its realm.

So, in order to simplify, I have considered only single-stage 100-mile footraces with 6-mile buffer. Thus, coveted races like Badwater, Fat Dog, Arrowhead 135 – all have to be left out. Having run on roads, trails, mountains, I have a special affection for trail runs so like any other list, the list might reflect a bias towards trail races despite all efforts to stay neutral. The selection criteria include – distance, challenges and threat the race imposes, historical nature and finish rate that reflects the odds of finishing that race if you sign up for all 15, the degree of self-sufficiency and special gear/skills needed to compete. My personal favourite Barkley Marathons has been left out with no ranking due to its changing nature every year. Runners swear of the race being 120-130 miles long, hence, it could not fit in. However, it still stays WORLD’s TOUGHEST. The Highlander 100 is yet to see its first edition and hence, is not ranked because of no finish rate data. What are the toughest 100 milers in the World?

Here is the ranked list of TOP 16 Most Challenging 100-mile Ultra marathons.

16. Patagonia Run 100

Type: Mountain Race  |   Where: Neuquén, Argentina

Key Challenge: Technical climbs, unpredictable weather 

The Patagonia Run takes place in San Martín de los Andes, Argentina, and is a unique challenge for trail runners. In the 100 mile race, runners make their way across technical and semi-technical terrain, combining mountain trails of varying steepness and uneven ground with a total elevation gain of approximately 9000 m (29527 ft). The highest point of the race is located at 1,998 meters above sea level (summit of Filo Chapelco). 95% of the course is on mountain trails. This off-road race represents a true test of endurance, in the midst of the unique and beautiful scenery of San Martin de los Andes framed by the lively colours of the fall season, which turns the event into a one-of-a-kind mountain ultramarathon experience

15. Alpine Challenge Australia

Type: Mountain Race  |   Where: Victoria, Australia

Key Challenge: Endless climbs, unpredictable weather 

Hosted in Alpine National Park, Victoria, The Alpine Challenge is one among most challenging trail ultramarathons in the southern hemisphere. With 7600 m (25000 ft) of climb and an equal descent over 6 major peaks including Mt Feathertop, Mt Hotham, Mt McKay, Spion Kopje, Mt Nelse and Victoria’s highest mountain, Mt Bogong and five river crossings, the race offers challenging weather conditions, from intense heat during the day or snowstorms and driving rain, to subzero temperatures at night. To add to the adventure, the course is generally unmarked, with few important signs. The course follows bushwalking trails and is generally easy to follow using map and GPS. With a generous cut-off of 42 hours, the race also features distances like 100km, 60km and 36 km.

14. Ultra Tour Monte Rosa

Type: Mountain Race  |   Where: Monte Rosa, Italy-Switzerland

Key Challenge: Endless climbs, high altitude, unpredictable weather 

The spectacular Monte Rosa massif, with 10 summits over 4000m, lies on the Swiss – Italian border. UTMR follows the wildly beautiful trails taking a challenging and diverse high-level route around this magnificent mountain. The race starts in Cervinia, the old alpine village at the foot of the Matterhorn on the southern side, scribes a circle around the huge massif of the Monte Rosa – a roller coaster of tough ascents and long descents and along high wild trails – and eventually drops to finish line in Grächen. Majestic mountains, wild high passes, spectacular valleys, remote hamlets, traditional villages, flower-filled meadows, leafy forests, mountain tarns, demanding ascents, breathtaking descents and miles and miles of superbly runnable trails – with an elevation gain of 11,200 m, the UTMR promises a delightful experience.

13. Ultra Trail du Mont Blanc (UTMB)

Type: Mountain Race  |   Where: Chamonix, France

Key Challenge: Very competitive, long climbs, unpredictable weather 

Ultra Trail du Mont Blanc is probably the most respected, competitive and toughest ultramarathon on this planet. Amid tens of thousands of application, 2000 participants get to start the race in the French Alps where they follow the route of the Tour du Mont Blanc through France, Italy and Switzerland. With cumulative elevation gain varying between 31000-34,000 ft, runners run 171 km with a target to finish under 46.5 hours. Being immensely competitive, runners have to collect 15 points from 3 ITRA certified races before they can send the application to the lottery for getting selected. Amid breathtaking landscapes, endless climbs, steep descents and unpredictable tough weather conditions, UTMB is the most unique and a must-do ultramarathon for anyone who embraces nature, pain and accomplishment all in one package with a remarkable festival atmosphere at the Start/Finish in Chamonix in France.

12. Ultra Trail Tai Mo Shan

Type: Mountain Race  |   Where: Tao Mo Shan, Hong Kong

Key Challenge: Long climbs, rough terrain, changing weather

The Ultra-Trail Tai Mo Shan is an ultimate trail running challenges from hills of Asia. By connecting local footpaths, forest trail, reservoir family walk, country trail, and ancient trail around the foothills of Tai Mo Shan, this 100 Miles course allows participants to enjoy majestic 360-degree views of Tai Mo Shan while experiencing the stunning natural beauty and culture of this region. The distance of 100 miles spread like a giant single loop with 42 hours cut off, see an elevation gain of 9032 m. The race offers other distance of 115 km and 50 km.

11. Ehunmilak Ultra-Trail

Type: Mountain Race  |   Where: Gipuzkoa, Spain

Key Challenge: Rough technical terrain, unpredictable weather 

Ehunmilak Ultra-Trail, which is run across 5 regions, goes through back roads and trails with an elevation gain of 11,000 m over a distance of 168 km. The start and finish lines are in Beasain and there is a maximum completion time of 48 hours. Ehunmilak is a circular route that goes through the towns of Beasain, Zumárraga, Urretxu, Azpeitia and Tolosa. The race involves climbing several mountain summits where conditions may become difficult due to darkness, wind, cold and rain, therefore one must carry compulsory security equipment.

10. Cruel Jewel 100

Type: Trail Race  |   Where: Georgia, USA

Key Challenge: Endless climbs, technical trail

The Cruel Jewel 100 is a 106-mile foot race deep within the Chattahoochee National Forest of the North Georgia Mountains. Consisting of 94 miles of trails, 12 miles of mountain roads, and 20 aid stations, the course offers tough, and sometimes technical, single track trails, ferns and old growth poplar trees, steep ascents and even steeper descents, a historic steel bridge spanning the Toccoa River, the Dragon’s Spine, lush green hardwood forests, rocks, roots and ridgelines. The course is out and back from Blue Ridge to Vogel State Park with an elevation gain and an equal loss of 30,000 feet.

9. PLAIN 100

Type: Trail Race  |   Where: Washington, USA

Key Challenge: Self-supported, Navigation, Endless climbs

The Plain 100 takes place on US Forest Service trails and roads in the Cascade mountains in the Lake Wenatchee, Entiat, and Chelan ranger districts in Washington. With approximately 85 miles of trail and 20 miles of forest service roads, all quite remote, and an elevation gain/loss of roughly 21,000 feet, the race is self-supported with one re-supply point after the first 100K. The only aid station (if you call them one) are creeks and rivers on the course and runners are required to carry all the food and necessary gear from the start, or from the resupply point. Runners have 36 hours to finish this race that boasts of a fairly difficult unmarked course with great scenery and no support.

8. Swiss Peaks 170

Type: Trail Race  |   Where: Bouveret, Switzerland

Key Challenge: Remote trails, cold unpredictable weather, self-supported

The Swiss Peaks 170 starts at the foot of the “site of the twentieth century”, the Grande Dixence Dam and goes through the typical and insulated villages, discover abrupted slopes, wildlife lakes and the places of canton which are less discovered. The extremely challenging and technical trail of 106 miles features an elevation gain of 34,500 ft and loss of 38,500 ft and ends at Bouveret. The race features a night start at 8 pm with a cutoff of 53 hours. The race features other challenging distances of 35 km, 90 km and 360 km.

7. The Grand Raid Réunion

Type: Mountain Race  |   Where: La Réunion, Indian Ocean

Key Challenge: Endless climbs, high altitude, unpredictable weather 

The Grand Raid Reunion – La Diagonale des fous is a non-stop 164km long ultramarathon with gain and loss of 9,917m of elevation. The name tells you all you need to know – the diagonal of madmen. What makes it challenging is the tropical climate, temperatures that go from heavy rain to thick fog to extreme heat and sharp in a matter of hours. The wet volcanic rocks can be painful to run on and it’s easy to see why the Diagonale has mythical status. “If you’re prone to vertigo, pick another race, as some sections will scare the shit out of you,” says runners.

6. Ronda Dels Cims

Type: Mountain Race  |   Where: Andorra

Key Challenge: High mountains

Ronda Dels Cims is a part of Andorra Ultra Trail and features a distance of 106 miles with a whopping 13,500 m or 44000 ft of elevation gain and an equal loss. The course routes around the whole Principality of Andorra, including a visit to its highest point, Comapedrosa at an altitude of 2,942 meters, touching on the border and offers panoramic views, alternate zones of minerals, high mountain meadows, forests, glacial lakes, etc. Runners cross 16 passes of 2400 m or higher with an average altitude of 2085 m. With 13 supported aid stations, runners have generous 62 hours to finish the race. Ronda Dels Cims run alongside Euforia, which is 233 km long race on an unmarked trail with an elevation gain of over 20,000 m with 32 passes over 2500m.

5. H.U.R.T. 100

Type: Trail Race  |   Where: Hawaii, USA

Key Challenge: Technical trail, rough terrain, high humidity, unpredictable weather 

The HURT Trail 100-Mile Endurance Run (HURT 100) is conducted on trails located on the hills above Honolulu (O‘ahu, Hawai‘i) on the Makiki Trail System. Known for its challenging trails passing through the forest, along exposed ridges, and past vertical embankments, the race is designed for the most adventurous and extremely prepared to batter the technical trails. The course is divided into 5 loops on a moderately packed soil surface generously interspersed with roots, rocks, puddles, and mud wallows in a tropical rainforest with an elevation gain of 25000 ft including 4 stream crossings per loop. High humidity, heat and rains make HURT 100 one of the most challenging races in the world.

4. Dead Sheep Race

Type: Trail Race  |   Where: Wales, United Kingdom

Key Challenge: Technical trail, rough terrain, tight cutoff, unpredictable weather 

The Dead Sheep Race, infamous as British Barkley, has 5 laps of 20 miles each, to be completed under 30 hours. The terrain of open Welsh moorland and the technical route with a climb of 8000 ft in each loop itself conspire to makes the race ridiculously difficult even in fair weather conditions. The course is unmarked, and like Barkley Marathons, checkpoint locations are declared just before the start. Good navigation skills are key to success if any. Race Director clearly declares “If you can’t navigate very well with a map and compass, do not enter because you will get lost, could be injured or die on this course.” Unmarked trail, tough conditions, stiff cut-off makes this race an ultimate challenge. The race is yet to see its first finisher.

3. Hardrock 100

Type: Mountain Race  |   Where: Colorado, USA

Key Challenge: Endless climbs, high altitude, unpredictable weather 

Hardrock 100 is one of the toughest 100 milers out there runners seek to challenge once in their lifetime. Open to only 150 participants, the race is held in the San Juan mountains, starts from Silverton School and ends in the same spot, passing through Lake City, Ouray and Telluride along the way. With elevation gain and an equal loss of about 34,000 ft, a stiff cutoff of 48 hours is incredibly tough to chase when runners are exposed to forces like thunderstorm lightning, rain, hail on an extremely rugged terrain including steep scree climbs and descents, snow packs, river crossings, and boulder fields.  In order to complete the event, instead of crossing a finish line, runners are required to “kiss the Hardrock”, a picture of a ram’s head painted on a large block of stone mining debris. Every year the race is run in the opposite direction than the previous one, keeping it a tough nut to crack.

2. Ouray 100

Type: Mountain Race  |   Where: Colorado, USA

Key Challenge: Endless climbs, high altitude, unpredictable weather 

With over 41,862 ft elevation gain, 83,724 ft change, Ouray 100  is one of the toughest 100 milers you will ever attempt, claims the Race Director. Situated in the rugged and stunning San Juan Mountain range in southwest Colorado, it’s a low key event with no frills. Other than the ridiculous amount of climbing that will overwhelm the quads and lungs, the key challenge is the vast landscape, extremely fickle weather. 2018 Finisher Razvan Lazareanu describes the races as “pick 14 mountain summits and bring people in to run to the top, over and down to the other side (sometimes more than once), repeat non-stop with no rest for 2 days and 2 nights, throw in some crazy rain and hail, thunderstorms, altitude between 10,000 and 13,000 feet and then mix everything together really, really well and Ouray 100 is the result of all this.” The race starts and finishes at Fellin Park, runners must hole punch their bib at numerous unmanned out and backs along the route. Runners are allowed to have a pacer after half way mark and crew may be positioned at dedicated aid stations. Ouray, in many ways, is similar to Hardrock 100 which is much more competitive, which is a good training race for The Barkley Marathons.

1. The Baldy Marathons

Type: Mountain Race  |   Where: California, USA

Key Challenge: Unmarked off-trail route, endless steep climbing, sleep deprivation, tight cut-off, unpredictable weather 

Take five parts of Ouray, three parts of Barkley Marathons and one part of craziness; you get Baldy Marathons. Staged in California Baldy Marathons is a 5 loop 100-mile race with an elevation gain of about 50,000 ft. The unmarked 20-mile race course offers extreme terrain with ridiculous climbs and descents around Mount Baldy. Where the race is entirely self-supported, runners are allowed to have pacers after the first loop of 20 miles. Still in its initial years, the race is a fairly open concept and credits the quitters the distance they have accomplished – 20 miles, 50k, 40 miles and 100 km till the time it meets the cutoff. Runners have 60 hours to finish the 100 miles. The Baldy Marathons happens twice a year – May and September, and offers different challenges in both editions. So far, the race is Free and open for anyone who wants to challenge themselves.

Before you go, here are some honorary mentions that deserve all the respect in their geographical location and challenges they pose, however, they did not quite make it to my Top 16 World’s Most Challenging 100-mile Ultramarathons

– The Barkley Marathons

Type: Mountain Race  |   Where: Tennessee, USA

Key Challenge: Race entry, unmarked off-trail route, No GPS, endless climbing, sleep deprivation, tight cut-off, unpredictable weather

The Barkley Marathon is a flat 26.2 mile Boston Qualifier road race on a well-marked course. With aid station every mile, the race features massage stations and Spa centres every 5 miles and you have 12 hours to finish the race. Okay, I lied. The Barkley Marathons, a race that survived the media eyeballs for about three decades, is now a classic in ultrarunning following the popularity it got through 2012 Documentary – “A race that eats its young”. Staged in Frozen Head State Park, Tennesse, BM100 is told to be a 100-mile race, with 5 loops of 20 miles with cumulative elevation gain of 64000 to 66000 ft to be run under 60 hours, averaging 12 hours per loop. Anyone who has run there would vouch for each loop being 26-30 mile long. The route is not marked, GPS is not allowed, so no one knows the distance or elevation. Runners have to collect 9-13 pages from books placed on the race route to prove they completed the loop. Runners are allowed to have a crew, however, they can provide support only during the time between the end of the previous loop and the start of next loop. How to enter the race? The course map? – it’s all still a guarded secret, however, there are bits and pieces available on the internet. Race map is revealed during check-in and race may start anytime between midnight to next morning, an hour after the conch. Only 40 poor souls get to start this race every year and its history of 32 years, the race has featured only 15 finishers. There is a lot of information available online, so I’d rather leave this to you to search for yourself.

– The Highlander 100

Type: Mountain Race  |   Where: California, USA

Key Challenge: Unmarked off-trail route, endless steep climbing, sleep deprivation, tight cut-off, unpredictable weather

The Highlander is the ultimate challenge in mountain trail running. Claimed to be the toughest race out there, staged in Mount Baldy, California, the Highlander features a distance of 100 miles and a ridiculous elevation gain of about 63,500 ft to be completed under 66.6 hours. The unmarked 30-mile race course offers extreme terrain with dangerous climbs and descents around Mount Baldy. Like Barkley Marathons, the race is entirely self-supported. The race will see its opening edition in October, 2019, hence, it is unranked. So far, the race is Free and open for anyone who wants to challenge themselves. However, there is a small fee for renting the Spot device for tracking. The Highlander claims to cease once it has even one finisher of 100 miles who finished under the cutoff.

– Bromo Tengger Semeru (BTS) Ultra

Type: Mountain Race  |   Where: East Java, Indonesia

Key Challenge: Mountain climbs, steep slopes, Vast variation in weather 

Bromo Tengger Semeru Ultra Run race aims to challenge your inner spirit and physical state, as well as to provide race participants with magnificent natural beauty and environment of Bromo Tengger Semeru National Park in East Java – Indonesia at various altitude level. Running at the high altitude region of Bromo Tengger Semeru National Park, the race offers tracks with various sceneries in the background, such as sea of volcanic sand (2200 m) with low temperature and strong wind, rural back roads, forest path and prairie with a distant magnificent view of the highest mountain in Java, Mount Semeru (3676 m) and the tranquility of Lake Ranu Kumbolo (2,400 m). The 106-mile race is a single loop and has an elevation gain of over 8340 m with a cutoff of 46 hours.

– Chicamocha Canyon Race 100

Type: Mountain Race  |   Where: Chicamocha Canyon, Colombia

Key Challenge: Steep climbs, changing terrain, high altitude, unpredictable weather 

In Colombia there is the longest Canyon of South America. There is developed Chicamocha Canyon Race, the toughest trail of Colombia. Temperatures between 12 and 42 degrees Celsius, several vertical kilometers, trails in stone, varied flora and fauna, spectacular landscapes, a high difficulty of the route, contrasts of vegetation, weather and altitude, historic and colonial towns make the race a special experience. The 100 miles is a giant single loop with constantly changing terrain featuring an elevation gain of 8560 m.

– 100 Miles of Istria

Type: Mountain Race  |   Where: Istria,

Key Challenge: Steep climbs, changing terrain, high altitude, unpredictable weather 

The 100 miles of Istria stretches from the eastern part of Istria, over its highest mountain down to the mainland, and ends on the western part of the peninsula in the city of Umag. The race route offers – tough technical terrain, a little bit of coastering, old medieval towns, deep forests, city centers, old train route, muddy valleys, all spiced up with breathtaking panoramas. The course starts in the 3000 years old town Labin, climbs the Učka mountain and descends in Buzet, leading to the smallest town in the world, the town of Hum, then to the medieval pearl Motovun and back to the finish in Umag. 168 km with 6539 m of elevation gain, it is one demanding trail, more than just the numbers – claim organizers. Now in addition to the 100-mile race, runners can also select a shorter 110 km, 69 km or a 42 km route.

– The Northburn 100

Type: Mountain Race  |   Where: Northburn, New Zealand

Key Challenge: Constant climbs, unpredictable weather 

100 miles with an elevation gain of 10,000m (32,808feet) – that’s Northburn 100 for you. The course covers 3 loops, each loop starting and finishing in the same place, covers dry, hard, rocky terrain mostly over high country 4WD tracks but also includes some short sections of fence lines and sheep tracks. The weather in New Zealand is very dynamic, hence, you never know what you are going to get by end of the day. The first 50km loop takes you 2600m vertically up. The second loop of another 50 km takes runners further up by 3750m, followed by 4000 m more in the third loop of 60 km. The course is well marked with directional arrows, plastic poles and reflective tape at night. The race offers a reasonable cut-off of 48 hours.

– Hardcore 100

Type: Mountain Race  |   Where: Kayapa, Philippines

Key Challenge: Endless climbs, rain, heat and humidity

Hardcore 100 Miles (H1) – the first 100-mile trail race in the Philippines – with less than 10% of the route made up of concreted roads, and the rest, of single track trails, dirt/gravel paths, dry stream beds, grasslands, farmlands, forest trails and hanging bridges has elevation gain of approximately 37,098 ft. Runners may choose to run with a pacer 125 km onwards. H1 takes runners to two major peaks: Mount Pulag Tower (2800m) and Mount Ugo (2150m), and several hills and hamlets during the course of the race. It is also UTMB, Hardrock and Western States qualifier for 2019.

What’s your favourite 100-mile race(s)? Tell me in comments.