Best 100 Mile Races And Ultra Marathons In The US 2021

Written By Jasper Johnson

Jasper is a new member of the Ultra X team. A keen middle distance runner who is looking to up the distance to an ultra marathon, Jasper enjoys writing about all things running.

18 November 2020


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In this article we look to the birthplace of ultra running, the USA

Whilst we are considering all events under the ultramarathon category: single stage, multi stage, 100 mile races and more, the US is generally known for its epic 100 milers. Here we name the best of the best and review the ones that belong on every runner’s bucket list.

Western States Endurance Run

This is the big one. If there’s one ultra marathon you have heard of, it’s probably this. The Western States 100 claims to being the oldest 100-mile trail race. The race starts in the Olympic Valley, near the site of the 1960 Winter Olympics and ending 100.2 miles later in Auburn, California. Since its inception in 1974, Western States 100 has come to be synonymous with the toughest endurance tests in the world.

Following the same route since 1986, runners start from the valley floor up to ‘Emigrant pass’, climbing over 2550 ft in the first four and half miles. From the Olympic valley, (site of the 1960 Winter Olympic Games) you are taken up again, following the original trails used by the gold and silver miners of the 1850’s, runners travel west, climbing another 15,540 feet and descending 22,970 feet before reaching Auburn, a small town in the heart of California’s historic gold country. Most of the trail passes through remote and rugged territory.

Runners have 30 hours to complete the route, which, despite the considerable elevation, is generally considered ‘runnable’ (by the elites, anyway). The range in elevation means some miles are run on snow and others on scorching hot trails.

Western States attract some of the most elite competitors as well as being a Mecca for keen trail runners the world over, making competition for places fierce. First time entrants to the lottery entry have just a 1.3% chance of landing themselves a spot. Better get those entries in now…

Where: Squaw Valley, California
When: 26-27 June 2021
Distance: 161km
Elevation Gain: 5,500m
Terrain: Trail
Difficulty Level: Hard
Entry Price: $410

Western States 100 Endurance Run

Leadville Trail 100

The legendary “Race Across The Sky” Leadville Trail 100 started back in 1983 and takes runners one hundred miles across the extreme Colorado Rockies terrain  from elevations of 9,200 to 12,600 feet.

The Leadville Trail 100 was conceived as a way of bringing tourist money to the town after the local mine closed. Now it is one of the most iconic races on the US ultramarathon circuit. The course follows the Colorado Trail and is a gruelling out-and-back route, combining technical terrain with long and steep climbs, the most famous of which is the 3,740m high Hope Pass.

Nicknamed the ‘Two-Mile-High-City’, Leadville is located 3,100m above sea level, making running this ultra marathon, ultra hard. Serious altitude training is recommended before this race.

Over 800 people line up at the start most years, however, less than half usually finish…

Where: Leadville, Colorado
When: TBC 2021
Distance: 161km
Elevation Gain: 4,800m
Terrain: Trail
Difficulty Level: Hard
Entry Price: $335

Leadville Trail 100 Hope Pass

Badwater 135

Badwater 135 is the opposite of the Leadville 100. Runners start 85m below sea level, in Death Valley, one of the lowest places in the USA. Runners pass through some scary sounding places such as: Furnace Creek, Devil’s Cornfield, Stovepipe Wells and Lone Pine as they cover three mountain ranges, climbing nearly 4,500m overall, all the way up to the finish line on Mount Whitney, the tallest mountain on continental America.

To make this race even harder it takes place in July, not the nicest time of month to visit Death Valley! Temperatures reach well in excess of 40ºC (and sometimes as high as 50ºC!). Runners have been known to use ice baths and industrial sized fans to cool down at the checkpoints.

Running in the heat is something you will have to get used to, to take on this race. It make’s Ultra X Jordan (add link) seem like a walk in the park.

Where: Death Valley, California
When: 19-21 July 2021
Distance: 217km
Elevation Gain: 4,450m
Terrain: Mixed
Difficulty Level: Brutal
Entry Price: $1,495

Badwater 135 Death Valley

Hardrock 100

Many of the best 100 mile ultras are in Colorado, the beautiful and varied terrain making for quality racing, and Hardrock 100 is no exception. This race is hard and rocky (yes that pun was intended), consisting of a looped course of dirt trails and cross country running along the San Juan Range of the Rocky Mountains. The total elevation gain is more than 10,000m and runners travel above 3,700m of altitude, a lung wrenching 13 times, the highest point being the 4,285m summit of Handies Peak.

The finish is a unique one, with most runners managing to cross the finish line in about 40 hours, competitors must kiss the infamous ‘Hardrock’ at the end — a picture of a ram’s head painted on a large block of stone mining debris.

We recommend trying this tough unique race. However it isn’t for everyone, make sure you are well prepared to take this one on.

Where: Silverton, Colorado
When: 16 July 2021
Distance: 161km
Elevation Gain: 10,074m
Terrain: Mountains
Difficulty Level: Hard
Entry Price: $325

Hardrock 100 Ultra

Barkley Marathons

The founder of Barkley marathons is shrouded in a much mystery as the race is. Who is he? Why does he do it? Is he the devil reincarnate? Well perhaps not the last one but this race is known to take runners to dark places.

Cantrell (a.k.a. Lazarus Lake) is somewhat of a legend himself and the race is heavily influenced by his quirky personality. He named the event after his neighbour. (for no apparent reason other than to annoy him)

Barkley marathons went under the radar for many years till the Netflix documentary ‘The Race That Eats Its Young’ made it running folklore.

Supposedly a 100 mile race, competitors complete 5 20 mile loops However, it is known competitors will do at least 130 miles to complete the race. The route changes each year and is kept a closely guarded secret till a few days before the race. Competitors are told last minute when exactly the race will start, with race start times ranging from midnight to noon. Runners must self navigate their way through the wilderness picking up pages from books hidden in the wilderness. Competitors only finish if they have pages from every book and make it back within the 60 hour time limit. Not surprisingly only 14 runners have ever completed the race.

Where: Frozen Head State Park, Tennessee
When: Sometime in April (ish)
Distance: 160km (ish)
Elevation Gain: 36,600m (ish)
Terrain: Mountains
Difficulty Level: Brutal
Entry Price: $1.60

Barkley Marathons Yellow Gate

Grand to Grand

Grand to Grand is one of the big races in the USA. The location for this race couldn’t get much better, competitors start on the stunning northern rim of the Grand Canyon providing the best backdrop on the start line of any race we have seen. The conditions underfoot are expectedly sandy and rocky. The race is split up into marathon distances each day with a 85km long stage in the middle.

For the runners that make it to the finish line, they are greeted by the site of the Pink Cliffs of the Grand Staircase, one of the world’s most iconic geological formations and the rumoured burial site of Aztec gold.

While this may be the race of a lifetime, it has a price tag to match. However, considering the unbelievable panoramic views from the top of the canyons to the two-billion-year-old rock formations and isolated slot canyons in the valleys it’s easy to see why the £3550 is worth it for many.

Where: Grand Canyon, Arizona
When: 19-25 September 2021
Distance: 275km (7 days)
Elevation Gain: 5,499m
Terrain: Desert
Difficulty Level: Intermediate
Entry Price: $3,550

Grand to Grand Pink Cliffs Grand Staircase

Iditarod Trail Invitational

This race is a bit chilly…

Taking place in the infamous Alaskan snow, racers trek 1000 miles along the Iditarod Trail, expect temperatures to dip as low as -45ºC and rise to a toasty 1ºC. You can ski, bike or run this race but only the truly bold attempt this one on foot.

Only a handful of adventurers have finished this race since its inception in 2000. Icy temperatures aren’t the only thing to prepare for: gale force winds, blizzards and waist deep snow make running this race a superhuman effort. You have 30 days to make it through the snow covered route so self-sufficiency and resilience are a must to take this race on.

Where: Anchorage, Alaska
When: 28 February 2021
Distance: 1,609km
Terrain: Snow
Difficulty Level: Brutal
Entry Price: $1,750

Iditarod Trail Invitational 1000

Special Mention: Ultra X Mexico

This wouldn’t be an article on the Ultra X resource page without a mention of one of our favourite events which is just over the border from the States in Northern Mexico!

Ultra X Mexico takes competitors to the spectacular mountain trails of the Copper Canyons where the original ultra runners, an indigenous tribe called the Tarahumara Indians, famously featured in the book Born to Run, are based.

This is a proper bucket list event.

Where: Mexico, Copper Canyons 
When: 6-14 November 2021
Distance: 250km (5 days)
Terrain: Trail
Difficulty Level: Very Hard
Entry Price: $1495

Special Mention: Ultra-Trail Harricana of Canada (UTHC)

Although this one isn’t in the USA, it is just over the border in Canada and is up there as one of the best ultras around.

Runners get to explore the remote Canadian countryside, starting on the ski slopes of Mont Grand-Fonds and the trails of Charlevoix, runners get to experience a UNESCO biosphere reserve. The route offers narrow trails through untamed wilderness coupled with many summits en route providing stunning views of the Saint Lawrence River and the boreal forest below.

There are 4 races on offer but completion of the 125km race gives you 5 precious Ultra-Trail du Mont-Blanc (UTMB) Running Stones, so if UTMB is on your race calendar…

Where: Charlevoix, Quebec
When: 10-12 September 2021
Distance: 125km
Terrain: Trail
Difficulty Level: Intermediate
Entry Price: $387

Ultra-Trail Harricana of Canada (UTHC)

Special Mention: Spartan Trail

Known for its obstacle course races, the Spartan organization has recently taken to trail running, by partnering with some of the best known races on the planet, Lavaredo Ultra Trail, Patagonia Run and others to create a Trail World Championships. The inaugural event was cancelled in 2020 due to you know what but for all ultra-junkies the arrival of Spartan in the trail scene is definitely one to watch.

Expect things to go one of two ways…

Want to see more incredible ultra marathons from every continent? Recently, we listed the:



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