9 Legendary 100-Mile Ultramarathon Races

Trail Running

April 12, 2024

Running can be an addictive sport. One minute you're tackling your first 5K, the next you're wondering just how far you can go. If you want to push yourself to the mental and physical limits, here are nine legendary ultramarathons that will help you do just that.

If you’re a runner, you might have completed a 10K or half marathon and thought about doing a marathon. If that’s you, the step up from a marathon to a 100-mile race is not as big as you might think. After all, during a marathon you usually run as fast as you can for three, four, or five hours until you collapse over the finish line, completely spent.

One-hundred-mile races, on the other hand, are taken at a significantly more leisurely pace. Most runners walk up inclines to save their legs, there are multiple aid stations providing fuel and hydration, and some even have beds so you can take a short nap to recuperate.

So if you’re thinking of stepping up the distance, here are 9 of the best 100-mile races to aim for.

Ultra Trail du Mont Blanc (UTMB)

Location: Chamonix, France
Date: August

The one most runners have heard of, this 105-mile mountain ultra is over-subscribed for good reason: traversing the iconic Mont Blanc in one loop on hiking trails passing through France, Italy, and Switzerland makes it a race like no other on Earth.

Starting and ending in Chamonix, France, UTMB attracts some of the world’s best runners, as well as a whole range of amateur runners from across the globe, all looking to pit themselves against the distance and elevation. The challenge of completing 105 miles, with 32,000 feet / 10,000m of elevation gain within a 46.5-hour cut-off is what draws thousands of runners each year, along with the views, the crowds, and the hospitality.

Western States 100

Location: Olympic Valley, California
Date: June

Gaining a place on the start line of the world’s oldest foot race is a challenge in itself — there are a mere 369 spots up for grabs each year, so a strict lottery system is in operation. What's more, you can only get a place in the lottery if you have completed one of the qualifying races.

The race is popular for many reasons, not least the challenge of the terrain and the change in altitude. From the start in Olympic Valley where you scamper across snow-covered trails, to the long descents and searing heat as you progress, to the famous Rucky Chucky river crossing and the finish on the track in Auburn’s Placer High School athletics stadium.

Arc of Attrition

Location: Cornwall, UK
Date: January

A 100-miler that takes in the most extreme point of the English south coast, the Arc of Attrition is building a reputation as one of the most grueling, yet stunning, centuries in the world.

It follows the arduous and challenging South West Coast Path – one of the longest coastal paths in the world – from Coverack to Porthtowan. Running on the coastal path means that you’ll have the English Channel followed by the Atlantic Ocean’s ferocious, battering winds to your left for the entire journey. You’ll encounter miles of sand dunes, hours of darkness (the race is run in January), and ceaseless outcrops of toe-stubbing rocks on your way to the finish, where you can feast on well-deserved fish and chips.

Hardrock 100

Location: Silverton, Colorado
Date: July

Another 100-miler that’s a challenge in itself to secure a place in – Hardrock 100 uses a lottery system for entry, and the list of races that qualify you for that lottery is short and brutal. The race also gives back to the trail running community by requiring entrants to commit to volunteering for eight hours building local trails or helping at aid stations.

The route is formidable — taking place in the San Juan Mountains on average at around 10,800ft / 3,300m. It crosses 13 mountain passes, gains a total of 32,800ft / 10,000m, peaks at 14,045ft / 4,281m, and alternates direction every year. As a result, it’s aimed at the most experienced, prepared ultra-runners, and is limited to 150 places, so be forewarned if you’re thinking of applying. If you do get in though, you’ll experience something few other runners have experienced. Just make sure you’re fully acclimatized…

Lakeland 100

Location: Coniston, UK
Date: July

A brutal and beautiful British 100 for many reasons, not least as it’s an unmarked route through the Lake District - an area known for its strength-sapping fells, foot-sucking bogs, and remote wilderness.

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A total of 21,000ft / 6,400m elevation makes it a challenge in terms of climbing, although unlike a mountain ultra, it’s more of a constantly undulating route. The weather adds a problem-solving element — even in July, expect every type of British precipitation going hand-in-hand with cap-removing winds and plummeting temperatures overnight. It’s also an unmarked course, so your compass skills should be on point (or you should at least know how to work your watch’s GPS properly).

Grand Raid des Pyrenees

Location: Vielle-Aure, France
Date: August

The Pyrenees’ version of UTMB practically matches the elevation gain (32,000ft / 9,800m). With the highest point at a vertiginous 9,186ft / 2,800m, it’s a true test of quad strength, endurance, and mental resilience.

The weather can play havoc for runners, too — despite taking place in August, at altitude it can change rapidly, with rain, hail, thunderstorms, and thick fog combining to test your resilience.

But everyone who’s taken part would agree the route makes it all worthwhile: breathtaking summits, empty ski resorts, alpine hamlets, desolate pine forests, and lush meadows, with long ascents and equally long descents and views that you’ll still be thinking about months later.

Ultra-Trail Snowdonia by UTMB

Location: Snowdon, Wales
Date: May

Wales’s highest mountain at 3,560ft / 1,085m, Snowdon is not high when compared to some of Europe’s other monster peaks, but the technical terrain and changeable Welsh weather combine to give it the label ‘the UK’s most Alpine trail race’.

This 100-miler is challenging for many reasons, not least because miles of it are barely runnable due to either the number of rocks underfoot or the steepness of the ascent. But those who complete it will see parts of the Snowdonia National Park that usually you’d have to trek for miles to see.

Ultra Tour Monte Rosa

Location: Grächen, Switzerland
Date: September

If you thought UTMB and Hardrock 100 upped the elevation stakes, the UTMR takes it a step further with its astounding 38,000ft / 11,600m of ascent packed into 100 miles.

Starting and ending in the Swiss mountain town of Grächen, it winds up to the Italian border at 10,800ft / 3,295m. Along the way, you’ll be treated to views of icons of the mountain world, including Matterhorn, Weisshorn, and Monte Rosa massif.

The race was founded and designed by ultrarunner Lizzy Hawker, five-time winner of UTMB, as a kind of ‘dream’ race that would push her to her limits. The result is a worthy entrant on this list.

Leadville Trail 100 Run

Location: Leadville, Colorado
Date: August

The race that has put Colorado’s former silver mining town of Leadville on the map, the Leadville 100 ultramarathon takes place in tandem with the 100-mile mountain bike race the week before, with some hardy (read: punishment-seeking) athletes taking part in both.

The route is an out-and-back, winding 50 miles up Sugarloaf Mountain, before rising to Hope Pass, which runners descend then run/hike back over on their return leg. Strikingly, it all takes place at altitude, never dropping below 2,700m (hence its nickname of ‘The Race Across the Sky’), so, like Hardrock, some acclimatisation beforehand is advised if you live at sea level.

Written by

Howard Calvert

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