Ultramarathon

An ultramarathon, also called ultra distance or ultra running, is a footrace longer than the traditional marathon length of 42.195 km. Various distances, surfaces, and formats are raced competitively, from the shortest common ultramarathon of 31 mi and up to 3100 miles. World Championships are held by the International Association of Ultrarunners (IAU) for 50 km, 100 km, 24 hours, and ultra trail running. The Global Organization of Multi-Day Ultramarathoners (GOMU) holds World Championships for 48 hours and 6 days. World Records are ratified and recognized by World Athletics (50 km and 100 km), the IAU (50 km up to 6 days), and by GOMU (48 hours up to 5000 km).

Around 100 mi is typically the longest course distance raced in under 24 hours, but there are also longer multiday races commonly held as 48 hours, 200 mi, or more, sometimes raced in stages with breaks for sleep.

The oldest and largest ultramarathons are on road, including the Comrades Marathon (over 10,000 finishers annually) and Two Oceans Marathon (over 6,000 finishers annually). The world's longest certified Footrace is the Self-Transcendence 3100 Mile Race. Many ultras have historical significance, including the Spartathlon, based on the 246 km run of Greek messenger Pheidippides from Athens to Sparta during the Battle of Marathon in a day and a half to seek aid against the Persians.



There is also overlap with the sports of trail running and mountain running. Some 100 mi races are among the oldest and most prestigious events, especially in North America. The oldest and also the largest trail race is the SainteLyon 78km in France (over 5,000 finishers annually).

Overview
There are two main types of ultramarathon events: those that cover a specified distance or route, and those that last for a predetermined period (with the winner covering the most distance in that time). The most common distances are 50 km, 50 miles (80.47 km), 100 km, 100 mi, and continue up to the longest certified race distance of 3100 miles. Timed events range from 6, 12, and 24 hours to 3, 6, and 10 days (known as Multiday races). Timed events are generally run on a track or a short road course, often one mile (1.6 km) or less.

The format of ultramarathons and the courses vary, ranging from single loops (some as short as a 400 m track), to point-to-point road or trail races, to cross-country rogaines. Many ultramarathons have significant obstacles, such as inclement weather, elevation change, or rugged terrain. Usually, there are aid stations, whether every lap of a track, small road or trail loop courses, or extending up to perhaps 20 to 35 km, where runners can replenish food and drink supplies or take a short break.

There are some self-supported ultramarathon stage races in which each competitor has to carry all their supplies including food to survive the length of the race, typically a week long. The Marathon des Sables 6-day stage race in Morocco and the Grand to Grand Ultra in the US are examples.

The International Association of Ultrarunners (IAU) organises the World Championships for various ultramarathon distances, including 50 km, 100 km, 24 hours, and ultra trail running, which are also recognized by World Athletics. Many countries around the world have their own ultrarunning organizations, often the national athletics federation of the country, or are sanctioned by such national athletics organizations.

50-kilometer and 100-kilometer races are recognized as World Records by World Athletics, the world governing body of track and field. The International Association of Ultrarunners recognizes IAU World Records for 50-kilometers, 100-kilometers, 6 hours, 12 hours, 100 miles, 24 hours, 48 hours, and 6 days. The Global Organization of Multi-Day Ultramarathoners (GOMU) recognizes Multiday race World Records for standard and non-standard distances and times between 48 hours and 5000 km.

There are ultramarathon Racewalking events that are usually 50 km, although 100 km and 100-mile (160 km) "Centurion" races are also organized. Furthermore, the non-competitive International Marching League event Nijmegen Four Days March has a regulation distance of 4 × 50 km over four days for those aged 19 to 49.

In 2021, concerns were raised about planning and medical care available for ultramarathons in China, after dozens of racers died from hypothermia and at least one from a heart attack while competing in an ultramarathon in the Yellow River Stone Forest. The government later announced a ban on "extreme" competitions.

In August 2023, a partnership between Ultra-Trail du Mont-Blanc (UTMB) and Ironman Triathlon was announced and the new formation of the UTMB World Series, an ultra-distance circuit that culminates with UTMB held in August. Concerns have been raised about rising entry fees, homogenization of racing experiences, and bulldozing of smaller events.

IAU World Record performances
Until 2014, the IAU maintained lists of the world best performances on different surfaces (road, track, and indoor). Starting in 2015, the distinction between the surfaces was removed and the records were combined into a single category. Some governing bodies continue to keep separate ultramarathon track and road records for their jurisdictions.

Starting in January 2022, the IAU began to recognize and ratify performances as IAU World Records. World Athletics also began to ratify the 50k distance as a World Record for both mixed and women, respectively, along with 100k.

Record performances at IAU labelled events that have not yet been ratified are as follows:


 * At the Jackpot 100 US Championship in February 2022, Camille Herron set a 100-mile mark of 12:41:11. However, there were problems with the course arrangement and distance.
 * Miho Nakata ran 270.363 km in 24 hours in December 2023.

The IAU World Records as of May 2024 are as follows.

Women
Until 2021, the IAU also kept records for 1000 km and 1000 miles. The final records were:

Global Organization of Multi-Day Ultramarathoner World Record performances
The Global Organization of Multi-Day Ultramarathoners (GOMU) was founded in October 2021 to recognize Multiday race World Records that are not recognized by the International Association of Ultrarunners.

GOMU recognizes the IAU-ratified World Records for 48 hours and 6 days. They recognized standard times/distances for 48 hours, 72 hours, 6 days, 10 days, 500 miles, 1000 miles, 2000 miles, 3000 miles, 3100 miles, 500 km, 1000 km, 2000 km, 3000 km, 4000 km, and 5000 km. They also recognize records for a number of non-standard formats (4 days to 49 days, 200 miles to 2900 miles, and 300 km to 4900 km).

IAU World Championships
There are four IAU World Championships: the IAU 100 km World Championships, IAU 50 km World Championships, IAU 24 Hour World Championship, and the IAU Trail World Championships.

GOMU World Championships
GOMU World Championships are held for 48 hours and 6 days to encourage multi-day athletes from around the world to come together, compete on a level playing field, and aspire for world, national, age-group, and personal records.

Record holders
The following is a selected list of world or international-record-holding, or world-championship-winning, ultramarathon runners.


 * Al Howie, record holder for the trans-Canada, 7295.5 kilometers in 72 days, 10 hours and 23 minutes
 * Aleksandr Sorokin, IAU World Record holder for 6h, 12h, 24h, 100 kilometers and 100 miles; Winner of the IAU 24 Hour World Championship and Spartathlon
 * Ann Trason, fourteen-time winner Western States 100; 2-time winner of the Comrades Marathon; World 50 mi record holder (5:40:18), American 100k record holder (7:00:48)
 * Anna Frost, 2-time winner Hardrock 100, 2-time The North Face Endurance Challenge, Transvulcania, Maxi-Race du Lac d'Annecy
 * Arthur F. H. Newton, 5-time Comrades Marathon winner, former world records for 50 and 100 miles and 24-hours
 * Beth Pascall, winner of the Western States Endurance Run, Ultra Trail Cape Town (course record), The Canyons Endurance Run (former course record), and FKT of the Bob Graham Round
 * Bongmusa Mthembu, 3-time winner of the Comrades Marathon and the Two Oceans Marathon, the African record holder for 100 km
 * Bruce Fordyce, 9-time Comrades Marathon winner, former world records for 50 miles and 100 km
 * Camille Herron, Only athlete to win the 50 km, 100 km, and 24 Hour world championships; Spartathlon Champion and course record; Comrades Marathon and JFK 50 Mile Champion; 50 mile World Best and IAU World Records for 100 miles, 24h, 48h, and 6 days
 * Caroline Chaverot, winner of the 2016 Trail World Championships, 2016 Skyrunning World Championships Ultra, also winner of UTMB, Courmayeur-Champex-Chamonix, 2-time Lavaredo Ultra Trail, Transgrancanaria, Maxi-Race du Lac d'Annecy, Hardrock 100, Eiger Ultra Trail, Madeira Island Ultra Trail (cr), and Festival des Templiers
 * Carolyn Hunter-Rowe, world record 40 mi, 2-time IAU 100 km World Champion, winner Two Oceans.
 * Charles R. Lawrence, 50 mile IAU World Record
 * Courtney Dauwalter, wins and course records at: Ultra-Trail du Mont-Blanc (3-time winner), Western States 100 (2-time winner), Hardrock 100 (2-time winner), Transgrancanaria (2-time winner), and Grand Raid
 * Don Ritchie, world record 100 miles for 25 years, world record for 100 km for nearly 40 years
 * Edit Bérces, 24-hour treadmill world record; several Hungarian records
 * Ellie Greenwood, 2-time IAU 100k Championship winner, Comrades Marathon winner, winner of Courmayeur-Champex-Chamonix and Festival des Templiers, former course records at the Western States 100, JFK 50 Mile, and the Canadian Death Race
 * Fotis Zisimopoulis, 3-time winner of Spartathlon and course record holder, 2nd place at the IAU 24 Hour World Championship
 * François D'Haene, 3-time winner of UTMB and course record holder, 3-time winner of Grand Raid, 2-time of Madeira Island Ultra Trail and course record, Maxi-Race du Lac d'Annecy
 * Frith van der Merwe, set former 50k world record en route to winning the Two Oceans Marathon, former downhill course record at Comrades Marathon
 * Gerda Steyn, winner and course records at Two Oceans Marathon (5-time winner), Comrades Marathon (both uphill and downhill courses),  and the Om die dam marathon
 * Ida Nilsson, 3-time winner Transvulcania and course record, 2-time The North Face Endurance Challenge, Swiss Alpine Marathon, and Ultravasan
 * Jasmin Paris, course record and overall winner of the Spine Race, first woman to finish the Barkley Marathons and 2-time Fun Run finisher, winner and course record at the Fellsman, former FKT at the Bob Graham Round
 * Jenny Hoffman, female coast-to-coast FKT of the United States in 47 days, 12 hours, 35 min
 * Jim Walmsley, former World record for 50 miles; World Long Distance Mountain Running champion; wins and course records at: Ultra-Trail du Mont-Blanc, Madeira Island Ultra Trail, Western States 100 (4-time winner), JFK 50 Mile, Tarawera 102k; Grand Canyon rim-to-rim-to-rim FKT, and Ultravasan
 * Jonas Buud, 2015 IAU 100 km World Championships winner and 4-time silver medallist, 8-time winner of the Swiss Alpine Marathon, Ultravasan course record, 2nd at Comrades Marathon
 * Kaneenika Janakova, former course record for the Self-Transcendence 3100 Mile Race, holds multiday World Records for 19-49 days, several distances between 1400-2900 miles and 2100km-4900km.
 * Kilian Jornet, former course record for UTMB (4-time winner), Hardrock 100 (5-time winner), and Zegama-Aizkorri skymarathon (11-time winner), winner of Western States 100, 3-time Buff SkyRunner World Series champion, FKT ascent + descent for Matterhorn and Mont Blanc, former FKT for Kilimanjaro, Denali, Aconcagua, and the Bob Graham Round
 * Lizzy Hawker, 5-time winner of Ultra-Trail du Mont-Blanc, 2006 IAU 100 km World Championships winner, Spartathlon winner, former 24h world best holder
 * Mami Kudo, former women's 24h track world record holder (255.303 km, Soochow TPE, 2011), 2013 female winner of IAU 24 Hour World Championship
 * Miho Nakata, winner of the 2023 IAU 24 Hour World Championship and 24Hr World Record (pending ratification)
 * Nicky Spinks, four-time winner of the Fellsman, set FKTs for double Bob Graham Round (under 48 hours), Ramsay Round, and Paddy Buckley Round
 * Ollie Garrod, set 40 mile world record en route to winning the Barry 40.
 * Patrycja Bereznowska, 2017 IAU 24 Hour World Championship winner and former 24h world best holder; winner and former course records at Spartathlon and Badwater Ultramarathon; former 48h IAU World Record
 * Pau Capell, winner of the Ultra Trail World Tour (2018), UTMB, 3-time Transgrancanaria
 * Pete Kostelnick, best known for the overall coast-to-coast FKT of the United States in 42 days, 6 hours, and 30 minutes, 2-time Badwater Ultramarathon
 * Ragna Debats, gold at the 2018 and bronze at the 2016 Trail World Championships, winner of Marathon des Sables, Transvulcania, Courmayeur-Champex-Chamonix, and 2018 Skyrunning World Championship Ultra
 * Ruth Croft, winner of Festival des Templiers (2-time winner, course record), Western States, Transvulcania (course record), Courmayeur-Champex-Chamonix, Orsières-Champex-Chamonix (2-time winner), Speedgoat 50km, Tarawera Ultramarathon (2-time winner), Ultra Trail Cape Town, IAU Trail World Championships (2nd place)
 * Ryōichi Sekiya, four time IAU 24 Hour World Championship World Championship winner, two-time winner of Spartathlon
 * Sandy Barwick, Current/Former World Record holder for standard distances/times for 6 days, 10 days, 500 miles, 1000 miles, 2000 km, 4-17 days, and 400-1200 miles
 * Sandra Villines, former female coast-to-coast FKT of the United States in 54 days, 16 hours, and 24 minutes, Badwater Ultramarathon
 * Satu Lipiäinen, 12 hour IAU World Record holder, finished 3rd at the 2023 Spartathlon
 * Scott Jurek, 7-time winner of Western States 100, Hardrock 100, 2-time Badwater Ultramarathon, 3-time Spartathlon, former American record for 24-hour
 * Shingo Inoue, 2010 winner of IAU 24-hour run World Championship (273.708 km)
 * Sumie Inagaki, current women's 48-hour track world record holder (397.103 km, Surgeres FRA, May 2010), 2-time female winner of IAU 24-hour run World Championship, two time female winner of Spartathlon
 * Surasa Mairer, World Record holder for 1000 km and 1300 miles (18 days)
 * Takahiro Sunada, former men's 100 km Road world record holder (6:13:33, Lake Saroma Ultramarathon, 1998)
 * Ted Corbitt, "the father of American ultrarunning"; 1952 US Olympic team member; former American world record holder at various distances
 * Tete Dijana, 2-time winner of the Comrades Marathon and downhill course record
 * Tsai Wen-Ya, course record of 45+ days 12:28:44 at the 2023 Self-Transcendence 3100 Mile Race
 * Tomoe Abe, current women's 100 km Road world record holder (6:33:11, Lake Saroma Ultramarathon, 2000)
 * Wally Hayward, multiple winner of the Comrades Marathon, London to Brighton, and many other ultramarathons; set early world records
 * Xavier Thévenard, only trail athlete to have won all four Ultra-Trail du Mont-Blanc races including 3-time winner of UTMB
 * Yiannis Kouros, current or former holder of numerous world records between 24-hour to 1,000 miles, former course record holder of the Spartathlon

Ultramarathons by regions
Ultra Marathons are run around the world with more than 600,000 people completing them every year.

Africa
Several ultra-distance events are held in Africa.


 * Egypt has joined the Ultramarathon races with more adding up each year.
 * Hathor 100 km is a Trail ultramarathon race in Sinaï. With distances of 50 km, 100 km, and 130 km.
 * Qarun 66 km Trail Ultramarathon race. Dated on March of each year in the city of Faiyum with distances 44 km and 66 km.
 * South Africa hosts a number of notable ultra marathon events.
 * On road: the world's oldest and largest ultramarathon, the 87 km Comrades Marathon. Approximately 12,000 runners complete the Comrades each year, out of approximately 17,000 who start, with 23,961 competing in 2000.
 * The 56 km Two Oceans Marathon in Cape Town in the southern autumn attracts approximately 11,000 runners.
 * Off-road: The Salomon Sky Run is a grueling 100 km self-supported, unmarked trail race held in a particularly scenic part of the country.
 * The Namib Race is a six-stage race that takes place along the Skeleton Coast in Namibia. It is part of the 4 Deserts Ultramarathon Series.
 * The Washie 100 road race is the oldest one hundred miler road race in Africa.
 * Trail: The Peninsula Ultra Fun Run (PUFfeR) 80 km supported, unmarked trail run crossing the Table Mountain range in Cape Town South Africa.
 * The Grand Raid de la Réunion is held annually on Réunion in October, crossing the island over 163 km with an altitude gain of 9643 m. This race attracts 2,350 competitors, with 1,000 runners from overseas.
 * The Marathon des Sables is a 6-day stage race which covers 250 km through the Sahara desert in Morocco.
 * The Spanish Canary Islands off the African coast are the location of some prestigious ultramarathons, including the 46-mile Transvulcania.

Asia
Ultrarunning has become popular in Asia, and countries such as Japan, Taiwan, and South Korea have hosted IAU World Championships.


 * A night race called the Sundown Marathon has been held in Singapore annually since 2008, over a double marathon distance (84 km) up to 2010 and 100 km since then.
 * Clark Freeport Zone in the Philippines is the venue for two of the Philippines' premier ultramarathon events. The Clark Miyamit Ultra, known as CM50 a 60K and 50Mile Trail Ultramarathon that takes runners to traverse from Clark to the Aeta Villages, lahar bed, mountain ranges near Mt. Pinatubo and the iconic Miyamit Falls. Cardimax – Clark Ultramarathon is a road ultramarathon of 50K and 100K distances which brings and gathers ultramarathoners from aspiring ones to the most competitive elites.
 * In Israel, two major ultramarathon races are Mount to Valley relay race; over 215 km, from the hills of the Upper Galilee to the Jezreel Valley, and the Valley Circle race in the Jezreel valley; contains several distances, including 160 km and 200 km.
 * In the Cebu, Philippines, an All-Women Ultra Marathon race covering a distance of 50 kilometers is held annually on the weekend of International Women's Day since 2012.
 * India's first ultra-marathon, the Bangalore Ultra was held in 2007. Since 2010, Indian Himalayas have hosted La Ultra – The High, a 333 km course crossing Khardung La, touted to be the world's highest motorable mountain pass.
 * Indonesia's first ultramarathon race, Mount Rinjani Ultra (52K), was held in August 2013 and Indonesia's first 100K & 160K ultramarathon race, Bromo Tengger Semeru 100 Ultra, was held in November 2013. Tambora Challenge (320 km) held from 2015
 * Japan had its first 100 km event in 1987 as Lake Saroma Ultramarathon and hosted the IAU 100 km World Championship in 1994 (Lake Saroma), 1998 (River Shimanto) and 2005 (Lake Saroma). Japan hosts more than 50 ultramarathon events throughout the year, including the Trans Japan Alps Race (TJAR) (415 km with more than 26000 m cumulative altitude gain crossing Japan Alps, crossing Japan's mainland from Japan Sea to Pacific Ocean in 7 days), Hasetsune cup (71.5 km in steep foggy mountains) and the Ultra-Trail Mt. Fuji (161 km loop around World Heritage Mount Fuji with a cumulative altitude gain of about 9000 m).
 * Malaysia's first ultra trail marathon was founded in November 2011 and is known as the TMBT (The Most Beautiful Thing) in Sabah at Mount Kinabalu, South East Asia's highest mountain. The event has a 55% dropout rate and is a 3-point qualifying race for UTMB and a 2-point qualifying race for the 55-kilometer category of the event. This was followed by the Beaufort Ultra Marathon in Sabah organized in 2012 and a 60-kilometer endurance run under 35-39-degree Celsius heat with a 60% finish rate amongst runners. First 100 miles ultra-marathon road race, Putrajaya 100 Miles, was held on 22–23 November 2014.
 * Nepal hosts several ultramarathon races, including the Annapurna 100, the Kanchenjunga Ultra Marathon Trail Running Race and the Everest Ultra. Running a total of 1,504 km in a bit more than 24 days, Ryan Sandes and Ryno Griesel set a new FKT during March 2018 for the Great Himalaya Trail.
 * Northern Mongolia hosts an annual 100 km summer race, Mongolia Sunrise to Sunset.
 * Soochow International 24H Ultra-Marathon is held since 1999 in Taipei, and is an official IAU-registered event.
 * South Korea's first ultramarathon was held in 2000.
 * The Gobi March in northwest China was China's first ultramarathon, first staged in 2003. The Gobi March is part of the 4 Deserts Race Series.

Oceania, Australia, and New Zealand
Australia and New Zealand are hosts to some 100 organized ultramarathons each year. Additionally, a handful of runners have run the entire length of New Zealand, a distance of around 2200 km.

Australia

In Australia, the Westfield Ultra Marathon was an annual race between Sydney and Melbourne contested between 1983 and 1991. Greek runner Yiannis Kouros won the event five times during that period. Australia is also the home of one of the oldest six-day races in the world, the Cliff Young Australian 6-day race, held in Colac, Victoria. The race is held on a 400-meter circuit at the Memorial Square in the centre of Colac and has seen many close races since its inception in 1984. The 20th Cliff Young Australian six-day race was held between 20 and 26 November 2005. During that event, Kouros beat his existing world record six-day track mark and set a new mark of 1036.851 km. The Coast to Kosciuszko inaugurated in 2004, is a 246 km marathon from the coast to the top of Mount Kosciuszko, Australia's highest mountain.

Australia has seen a steep growth in ultrarunning events and participants in recent years. Many new races have come into inception, covering a range of ultramarathon distances from 50 km right through to multi-day events. The cornerstone of Australian Ultra events is such races as Ultra-Trail Australia 100, The Great North Walk Ultras, Surf Coast Century, Bogong to Hotham, Alpine Challenge, GC50 Run Festival, and the Cradle Mountain Run. The Australian Ultra Runners Association (AURA) has a comprehensive list and links of events and their respective results.

New Zealand New Zealand's first ultramarathon, called the Kepler Challenge, was held on a 60 km trail through Fiordland National Park. It has been running since 1988 and is one of the country's most popular races. New Zealand's Northburn 100 ultra mountain run is the first 100-mile (160 km) race through the Northburn Station. The Te Houtaewa Challenge has a 62 km race on a ninety-mile beach, in Northland. The runners have to contend with rising tides and soft beach sand and the March race dates often mean the race is run in the cyclone season. In 2014 the ultramarathon was postponed because of Cyclone Lucy. The Tarawera Ultramarathon is currently one of the most competitive ultras in New Zealand and part of the Ultra-Trail World Tour.

In December 2013 in Auckland, Kim Allan ran 500 km in 86 hours, 11 minutes, and 9 seconds, breaking the 486 km women's record.

In April 2013, a Feilding man, Perry Newburn, set a new New Zealand record by running 483 km without sleep at Feilding's Manfeild Park.

Ultramarathon running in New Zealand has a national body: the New Zealand Ultrarunners Association.

Oceania New Caledonia Trail Festival has several annual ultramarathon including the Ultra Trail New Caledonia 136 km / 6 000m D+ and the Endurance Shop Trail race 70 km / 3 000m D+ on Pentecost long Week end. The Trail des Cagous is another 60 km ultramarathon held in April.

Papua New Guinea has the Kokoda Challenge Race, an annual 96 km endurance race held in late August that runs the length of the historic Kokoda Track.

Papua New Guinea also has the Great Kokoda Race, a multi-stage 96 km (3-day) race held in early July where competitors run or walk the length of the Kokoda Track.

Europe
In Europe, ultrarunning can trace its origins to early documentation of ultrarunners from Icelandic sagas, or ancient Greece from where the idea of the Marathon, and the Spartathlon comes. The history of ultrarunners and walkers in the UK from the Victorian Era has also been documented. The IAU hosts annual European Championships for the 50 km, 100 km and 24 hours. The European Ultramarathon Cup is an annual cup event covering some of the biggest ultramarathon races in Europe. Also worth mentioning is the ultramarathon CajaMar Tenerife Bluetrail, the highest race in Spain and second in Europe, with the participation of several countries and great international repercussions. Besides trail ultramarathons, Europe features large road ultramarathons such as Spartathlon and the Millau 100K, which have gathered thousands of runners for the past 50 years.

There are over 300 ultramarathons held in Europe each year,. This includes the Harz Run in the Harz Mountains, the Irish Connemarathon, the British Spine Race and Welsh Dragon's Back Race which covers 315 km with 15,500m of height gain.

The UTMB, through France, Italy, and Switzerland has been considered the world's most competitive trail ultra. The other races in the UTMB festival, including the CCC, TDS, and OCC, are also significant events in the ultrarunning calendar.

In 2021 the Megarace was held. The race was 1001 km and was planned to be held on trails through Germany, Czech Republic, and Austria. Due to Covid, 2021, the course was modified to only go through Germany.

Antarctica
Due to logistics and environmental concerns, there are only a handful of ultramarathons held in Antarctica, and travel costs can mean entrance fees as high as $14,000. Ultramarathons in Antarctica include The Last Desert, part of the 4 Deserts Race Series, a multi-stage footrace, and the Antarctic Ice Marathon – a marathon and 100-kilometer race.

North America
The oldest existing ultramarathon in North America is the JFK 50 Mile, which began in 1963 as a push by President John F. Kennedy to bring the country back to physical fitness.

There are several 100-mile ultramarathons held annually in North America. The Western States Endurance Run is the oldest 100-mile trail run in North America. The race began in 1977, founded by Wendell Robie, of Auburn California.

The largest ultramarathon in North America is the Marine Corp 50km. The largest 100-mile trail run is the Javelina Jundred.

Some of flattest, or North American ultramarathons with the least elevation take place in Florida like the Long Haul 100 and the Skunk Ape 100 Mile Endurance Run.

The first mountain trail ultramarathon held in the United States was the 1911 Mount Baker Race (50K), in Bellingham, Washington. Runners raced by car or train to the trailheads, ran up and down Mount Baker 10,000 feet, and then returned to the city.

An early ultramarathon was held in Mexico in 1926, and at the time was part of the Central American Games. Tomas Zafiro and Leoncio San Miguel, both Tarahumara Indians, ran 100 km from Pachuca to Mexico City in 9 hours and 37 minutes. At the time, the Mexican government petitioned to include a 100 km race in the 1928 Summer Olympics in Amsterdam.

In 1928, sports agent C. C. Pyle organized the first of two editions of the 3,455-mile-long Bunion Derby (the first went along U.S. Route 66 from Los Angeles to Chicago before heading toward New York; the 1929 Derby reversed the route). Neither the race nor the accompanying vaudeville show was a financial success.

In the 1980s, Gary "Lazarus Lake" Cantrell and Karl "Raw Dog" Henn conceived the Barkley Marathons, an annual trail race held in March or April in Frozen Head State Park, Tennessee. The course is approximately 20 miles long with approximately 11,000 feet of vertical climb, and runners have 60 hours to complete five laps. The run is notorious not only for its difficulty but also for its secretive nature; entrants must undergo a selection process and entry dates and requirements are not announced, meaning entrants rely on word-of-mouth for details on how to enter. The first Barkley Marathons took place in 1986, and as of 2022, only fifteen runners have ever completed the 100-mile course.

Since 1997, runners have been competing in the Self-Transcendence 3100 Mile Race, which is billed as the longest official footrace in the world. They run 100 laps a day for up to 50 days around a single block in Queens, NY, for a total distance of 3100 mi. The current recordholder is Ashprihanal Pekka Aalto, at 40 days 09:06:21 for a daily average of 76.776 mi in 2015.

The Fastest known time (FKT) keeps track of supported and unsupported speed records for running, cycling, or hiking routes. Some notable North American routes include the Trans America Run, Pacific Crest Trail, Appalachian Trail, and the Grand Canyon Crossings.

In April 2006, the American Ultrarunning Hall of Fame was established by the American Ultrarunning Association (AUA). Candidates for the Hall of Fame are chosen from the 'modern era' of American ultras, beginning with the New York Road Runners Club 30 Mile race held in 1958. The Inaugural inductees were Ted Corbitt, a former US Olympian, winner of the aforementioned race in 3:04:13, and co-founder of the Road Runners Club of America, and Sandra Kiddy, who began her ultra career at age 42 with a world record at 50 kilometers, 3:36:56, and who went on to set a number of US and world ultra records.

The Yukon Arctic Ultra is described as the coldest and toughest ultra in the world, requiring racers to start from Whitehorse to Dawson City, Yukon, a distance of 430 miles (692 km) in 13 days under the territory's extremely cold conditions in February.

South America
There are a small number of ultramarathons in South America, but participation in the sport is increasing. The Brazil 135 Ultramarathon is a single-stage race of 135 mi with a 60-hour cutoff, held in Brazil. This is a Badwater "sister race". Several ultramarathons are held in Chile and with both local and international participation. Ultramarathons held in Chile include:
 * Atacama Xtreme 50K, 80K, and the first 100 Miles in Chile. One loop for each distance starting and finishing in San Pedro de Atacama at an avg. of 2,400 above sea level.
 * The Atacama Crossing, established in 2004, a 250 km (155-mile) ultramarathon which takes place in the Atacama desert, around San Pedro de Atacama, Chile, and crosses through the driest place on earth. There are six stages in seven days, with almost four marathons running in the first four days, then a 74 km stretch, then a rest day, and a final stage of 11 km. It is part of the 4 Deserts Series. The race covers rugged terrain, with a harsh climate and an altitude that averages 2500 m (8000 ft). The race uses the town of San Pedro de Atacama as its host town, and in 2012 the race began at its highest point of over 3,000m in the Arcoiris Valley.
 * The Endurance Challenge, a 10K, 21K, 50K, and 80K trail running race held in the Andes mountain range near Santiago. It is part of the global Endurance Challenge circuit. The race seeks to promote the sport, outdoor activity, and the use of mountain trails, taking care to have the lowest impact possible on the environment.
 * The Lican Ray-Villarrica Ultramarathon, a 70 km marathon that starts in Lican Ray, climbs Villarrica Volcano and ends in downtown Villarrica.
 * "Extreme Challenge Peru Ultra" at 210 km, 105 km, 50 km and 25 km. This is a race where participants run for 5 consecutive days traveling to Sierra (9,000 to 11,000 feet elevation), the desert (running on top desert dunes), the coast, and the last day at the high elevation jungle (5,900 feet elevation). Some participants also run shorter distances.
 * The Patagonian International Marathon, organized by NIGSA, takes place in Torres del Paine National Park, southern Chilean Patagonia. The event features four race distances: an ultramarathon (63 km), a marathon (42 km), a half marathon (21 km), and a 10K. Each distance has a different starting point, but everyone finishes in the same place. The event has the secondary goal of promoting the conservation of Chilean Patagonia and contributing to the sustainable development of the region through the planting of trees in the Torres del Paine National Park through the "Corre y Reforesta" (Run and Reforest) campaign run by the organization "Reforestemos Patagonia" (Let's Reforest Patagonia)
 * The Rapa Nui GrandTrail, an 80k ultramarathon that takes place on Easter Island, Valparaíso Region, Chile. This exotic trail, far out in the Pacific Ocean, takes in the famous Moai statues of the island.

Argentina There are several ultramarathon races in Argentina.

La Mision has been going on for almost 15 years. There are different editions, one in Villa La Angostura in Patagonia with 3 distances. 110 km with cumulative altitude gain of about 4500m, 160 km with cumulative altitude gain of about 8000m and 200 km with cumulative altitude gain of about 9000m. There is other edition of the race (Short & Half) in Villa San Javier, Cordoba with 2 distances, 35k and 70k.

In April 2019 for the 1st time UTMB took place in Ushuaia (Ushuaia by UTMB) A very tough race facing the wild Patagonia weather with 4 different distances, 35k, 50k, 70k and 130k. The race brings together in one competition all the landscapes and geographies of the southern Andes (forests, rocky terrains, mountains, hills, glaciers, lakes, rivers, and wetlands, among others) The race has a technical, non-stop format and is ruled by the principle of semi-autonomy.

Cerro Champaqui in Cordoba is the landscape of different races. Champa Ultra Race with 5 different distances, 8k / 18k / 26k / 42k, and 62k. Also the UTACCH – Ultra Amanecer Comechingón with 7 different distances, 16k, 26k, 42k, and 4 ultras of 55k, 70k, 110k, and 100 miles.

Ushuaia, at "the end of the world" also hosts Ultra Maratón Glaciar Martial with 3 different distances, 10k, 25k, and 50k.

International Trail Running Association
Many ultramarathon organizers are members of the International Trail Running Association (ITRA), an organization that promotes values, diversity, health, and safety during races, as well as working to further the development of trail running and helps to coordinate between the national and international bodies with an interest in the sport. ITRA also evaluates the difficulty of specific ultramarathon routes according to a number of criteria, such as the distance, the cumulative elevation gain, and the number of loops and stages. ITRA maintains a calendar of ultra Trail running events.

Nutritional Demands of Ultra-Marathons
Ultra-marathon running requires meticulous attention to nutrition for both training and racing. In training, daily caloric needs are influenced by factors like body weight, training duration, and terrain, with carbohydrates comprising around 60% of the macronutrient distribution. Proper hydration is crucial. In racing, energy intake, carbohydrate availability, protein intake, and strategies to offset dehydration are essential. GI distress can be minimized by avoiding concentrated carbs and saturated fats, with probiotics and prebiotics offering potential relief. Runners should be cautious with supplements and medications, avoiding NSAIDs, and carefully managing caffeine intake. Tailoring nutrition to individual factors is key for ultra-marathon success.