An ultramarathon, also called ultra distance or ultra running, is a footrace longer than the traditional marathon length of 42.195 kilometres. Various distances, surfaces, and formats are raced competitively, from the shortest common ultramarathon of 31 miles (50 km) 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, the IAU, and by GOMU.
Ann Trason is an American ultramarathon runner from Auburn, California. She set 20 world records during her career. Her world record of 5:40:18 at the 50 mile distance, set in 1991, was unbeaten until 2015. As of her induction into the Ultrarunning Hall of Fame in 2020, she was considered by many to be the most successful female ultrarunner of all time.
The Western States Endurance Run, known commonly as the Western States 100 or Western States, is a 100.2-mile (161 km) ultramarathon that takes place on California's Sierra Nevada Mountains trails each year on the last full weekend of June. Western States is the oldest and one of the most competitive ultramarathons in the United States, and is administered by the nonprofit Western States Endurance Run Foundation.
Scott Gordon Jurek is an American ultramarathoner, author, and public speaker. Throughout his running career, Jurek was one of the most dominant ultramarathon runners in the world, winning the Hardrock Hundred (2007), the Badwater Ultramarathon, the Spartathlon, and the Western States 100 Mile Endurance Run (1999–2005). In 2010, at the 24-Hour World Championships in Brive-la-Gaillarde, France, Jurek won a silver medal behind Shingo Inoue and set a new US record for distance run in 24 hours with 165.7 miles. In 2015, Jurek set the Fastest Known Time running record for the 2,189-mile Appalachian Trail.
The Leadville Trail 100 Run is an ultramarathon held annually on rugged trails and dirt roads near Leadville, Colorado, through the heart of the Rocky Mountains. First run in 1983, the race course climbs and descends 15,600 feet (4,800 m), with elevations ranging from 9,200 to 12,620 feet. In most years, fewer than half the starters complete the race within the 30-hour time limit.
Tim Twietmeyer is an Auburn, California-based ultramarathon runner and an engineering manager at Hewlett Packard, in Roseville in the U.S. state of California. Twietmeyer is also a mountain biker, road cyclist, and retired almost-scratch golfer and swimmer. He is best known for his five victories and unprecedented 25 sub-24 hour finishes at the 100-mile (160 km) Western States Endurance Run.
The Grand Slam of Ultrarunning is a set of four of the five most prestigious and oldest 100-mile races contested in the United States, comprising the Old Dominion 100 Mile Endurance Run in Virginia, the Western States 100 in California, the Vermont 100 Mile Endurance Run in Vermont, the Leadville Trail 100 in Colorado, and the Wasatch Front 100 Mile Endurance Run in Utah. A small number of people manage to complete four in one calendar year.
Andy Jones-Wilkins is an elite ultra runner and educator. He began running ultramarathons in 1996 and 100-mile ultras in 2000, and became known for frequently finishing among the top few, without ever winning a race. This included, in 2005, coming in 2nd overall in the Western States 100 Mile, the Angeles Crest 100 Mile, and the Rocky Raccoon 100 Mile, though he won the Where's Waldo 100k. This changed in 2007, when he took first place in both the Vermont 100 Mile and the Grand Teton 100 Mile, also setting a new course record in the Grand Teton 100 Mile.
Nikki Kimball is an American distance runner specializing in the Ultramarathon. She ran her first 100-mile race at the Western States 100 Mile Endurance Run in 2004, and was the female winner. She was the winning female at Western States again in 2006 and 2007, becoming only the third woman to win Western States three times. In 2014, she won the Marathon Des Sables multi-stage endurance race on her first attempt. Prior to running, her main sport was cross-country skiing. She was crewed at the 2007 Western States by U.S. Senator Max Baucus of Montana, where Kimball lives. She lives in Bozeman, Montana.
Hal Koerner is an American distance runner specializing in ultramarathon running. He is the owner of a specialty running store, Rogue Valley Runners, located in the mountainous Southern Oregon town of Ashland. He is one of the subjects of JB Benna's feature-length documentary "Unbreakable: The Western States 100".
Timothy Olson is an American ultra-runner who was the former recordholder for the Pacific Crest Trail in 51 days, 16 hours and 55 minutes. He won the Western States 100 in 2012 and 2013, including the former course record of 14 hours, 46 minutes and 44 seconds in 2012.
Harvey Sweetland Lewis is an American ultrarunner.
Lake Sonoma 50 is a 50-mile ultra marathon race held near Healdsburg, California. The course circumnavigates the Warm Springs arm of Lake Sonoma on hiking trails. It takes place annually on the second Saturday in April. The race was first run in 2008. In recent years it has become one of the most highly competitive ultra marathons in the United States.
Kristin "Krissy" Moehl is an American ultramarathon athlete who specializes in trail running. In 2005, Moehl became the youngest woman to complete the Grand Slam of Ultrarunning, which included a gold medal at the Vermont 100 Mile Endurance Run.
Alissa St Laurent is a Canadian ultramarathon runner. She began her ultra career in 2013 and has competed for the Canadian National team in 100km World Championships and the 2015 IAU Trail World Championships. She holds numerous course records, including those for the Sinister 7 100-mile and the Lost Soul 100-km ultramarathons. She received national attention after becoming the first female to win the 125-km Canadian Death Race outright in 2015 and her later comments in the media encouraging more women to take up competitive sports such as ultrarunning.
Rory Bosio is an American ultramarathon runner. She is specializes in mountain running, and won the 2013 and 2014 Ultra-Trail du Mont-Blanc.
Gerald Tabios is a Filipino long-distance runner and Ultramarathon runner. Among his most notable races in the United States is the Badwater Ultramarathon. This is an annual race that stretches 135 miles through Death Valley, California in July and ends after a steep climb of Mount Whitney. In the world of Ultramarathons this race, where temperatures often reach 130 °F, is frequently coined "The Toughest Foot Race in the World." Tabios is a 7-time Badwater 135 finisher.
Speedgoat 50k is an international skyrunning competition held for the first time in 2008. It is run every year in Little Cottonwood Canyon in July and includes a marquee 50K race and typically one or more other distances/challenges.
Courtney Dauwalter is an American ultramarathon runner and former teacher. Widely regarded as one of the world's best female trailrunners, Dauwalter became in 2023 the first person ever to win Western States 100, Hardrock 100 and the UTMB, three iconic 100-mile races, in the same year.
Gary Cantrell, known as Lazarus Lake, is an endurance race designer and director. His races include the Barkley Marathons, Big's Backyard Ultra, the Barkley Fall Classic, Vol State 500K, A Race for the Ages, the Last Annual Heart of the South, and the Strolling Jim 40. In 2018, Lake covered the United States on foot, starting in Rhode Island and ending in Oregon.
United States 
