This is the home base for the most legitimate 100-mile-plus ultramarathons in America — full race specs, course descriptions, aid station breakdowns, and recent results, race by race. We built this list out one race at a time, since data like cutoffs, elevation profiles, and qualifying status deserves to be accurate rather than approximate. All 48 currently-active races from our original 50-race list are now live, organized below by region. (The other two — Oregon’s Pine to Palm 100 and Massachusetts’s Stone Cat — were dropped after Pine to Palm was discontinued by its longtime race director and Stone Cat turned out never to have offered a 100-mile distance.)
West — California, Oregon, Nevada, Hawaii
Western States 100
The oldest 100-mile trail race in the world, and the one every other American hundred-miler still gets measured against.
Angeles Crest 100
Running since 1986, and one of the most volatile courses in American ultrarunning — fire, drought, and wilderness closures have forced a course change almost every year this decade.
Rio Del Lago 100
Runnable, well-organized, and forgiving by 100-mile standards — a common pick for a first hundred.
San Diego 100
An old-school favorite — 85% singletrack through five distinct terrain zones, and a regular Western States qualifier.
Hood Hundred
A newer race (first run in 2024) already carrying real weight — a fast, runnable first 70 miles into a genuinely tough final 30 on Mt. Hood’s dry eastern side.
Tahoe Rim Trail 100
“A glimpse of heaven, a taste of hell” — the race’s own tagline, earned by the Red House Loop and 90-degree valley heat waiting at the bottom of a course that spends most of its time above 8,000 feet.
HURT 100
Five identical loops through Honolulu’s rainforest mountains, 24,500 feet of climbing packed into a course that never gets above 1,900 feet — technical, wet, and relentlessly repetitive by design.
Mountain West — Colorado, Utah, Wyoming, Montana, Idaho
Hardrock 100
“Wild and Tough” — the race’s own slogan. A 146-runner field chosen by lottery, an average elevation above 11,000 feet, and a finish-line rock every winner has to kiss to stop the clock.
Leadville Trail 100
“Race Across the Sky” since 1983 — an out-and-back where Hope Pass gets climbed twice, and the silver-and-gold belt buckle is the whole point.
High Lonesome 100
Five miles above treeline on the exposed ridge that gives the race its name, with two out-and-back trips up Laws Pass and a closing 20 miles of Colorado Trail to get home.
Run Rabbit Run 100
Hares start at 1pm, Tortoises at 9am, both chasing the largest prize purse in American 100-mile racing — $20,000 to the winners — over Buffalo Pass and Mount Werner in fall-colored Routt National Forest.
Wasatch Front 100
One of the original members of ultrarunning’s Grand Slam, point to point across the heart of the Wasatch Range, requiring a documented DNF-and-requalify if a runner is timed out early.
The Bear 100
Named for a legendary grizzly, run each fall through red maple and golden aspen from Logan, Utah to Bear Lake, Idaho — finish under 24 hours and take home the Wolverine Buckle.
Zion 100
Four steep climbs onto high-desert mesas above the Virgin River, with West Temple and The Watchman in constant view — a spring 100-miler through southern Utah’s red rock instead of alpine forest.
Bighorn 100
An out-and-back through the Little Bighorn and Tongue River drainages of the Bighorn National Forest, consistently ranked among the ten hardest 100-milers in the country — and a Hardrock and Western States qualifier.
Crazy Mountain 100
Point to point across the Apsaalooke people’s Awaxaawippíia — “ominous mountain” — through jagged cliffs, scree fields, and high alpine lakes, between two multi-generational Montana cattle ranches. A Hardrock and Western States qualifier that doesn’t take first-timers.
IMTUF 100
Eight high passes through the Salmon River Mountains during peak elk rut, with “TUF footing” the race’s own shorthand for what’s underfoot — a Hardrock qualifier since 2012.
Southwest — Arizona, Texas
Javelina Jundred
“The original costumed 100 mile trail run party,” run Jalloween weekend in the Sonoran desert — and a Western States 100 Golden Ticket race where the top two men and women automatically qualify.
Mogollon Monster 100
Six trips up and down the Mogollon Rim on 30-45% grades — “finishing isn’t just something you do, it’s something you decide,” in the race’s own words. A Hardrock qualifier and, new for 2026, a Western States qualifier too.
Saddles 100
A single loop through Prescott’s granite dells and ponderosa pine backcountry, linking together the area’s standout trails — a newer race quickly establishing itself as a legitimate high-desert 100.
Rocky Raccoon 100
Five 20-mile loops around the lake at Huntsville State Park on soft pine-needle trail — the race that built its reputation as the friendliest place in the country to run your first, or fastest, 100 miles. A Western States 100 qualifier.
Midwest — Wisconsin, Illinois, Minnesota, Indiana, Ohio, Kansas, South Dakota, Michigan
Kettle Moraine 100
A single point-to-point-and-back journey across the glacially-carved Kettle Moraine State Forest on the Ice Age Trail — one leg of the Midwest Grand Slam, and a Western States 100 qualifier despite never leaving Wisconsin’s low hills.
Hennepin Hundred
A flat, fast point-to-point journey down the historic Hennepin Canal towpath across rural northern Illinois — a Western States 100 qualifier every year since 2019, and one of the best shots in the country at a personal-best 100-mile time.
Tunnel Hill 100
The fastest hundred in the world. A dead-flat, out-and-back crushed-limestone rail-trail through the Shawnee National Forest that has produced five world records, including Camille Herron’s untouched 12:42:40 open women’s 100-mile world record — and a genuine shot at a first, or fastest, 100-mile finish for everyone else.
Superior 100
A rugged, relentless, remote point-to-point across the Sawtooth Mountains on the Superior Hiking Trail, paralleling Lake Superior the entire way. Founded in 1991, it’s the 9th oldest 100-mile trail race in the United States and one of the true legacy hundreds.
Indiana Trail 100
Four 25-mile loops through the rolling hardwoods and lakeshore trails of Chain O’Lakes State Park — a Midwest Super Slam leg and Western States 100 qualifier known for deep, dedicated volunteer support.
Burning River 100
An out-and-back through Cuyahoga Valley National Park and the Summit Metro Parks, tracing the historic Ohio-Erie Canal Towpath past the very river that gave the race its name. The 3rd leg of the Midwest Grand Slam of Ultrarunning, and a Western States 100 qualifier where every finisher earns lottery entry.
Mohican 100
Four loops through the 5,000-acre Mohican Memorial State Forest, one of the nation’s oldest 100-mile races and reportedly the longest continuously run ultramarathon in the country. A Western States 100 qualifier and one leg of the Midwest Grand Slam of Ultras — deceptively hard for a Midwest race, with nearly double the climbing of nearby Indiana Trail 100.
Heartland 100
An out-and-back across the open range of the Flint Hills tallgrass prairie on 99% backcountry gravel road — remote, exposed, and unmistakably Kansas. A required leg of the Kansas Grand Slam of Ultrarunning.
Lean Horse 100
An out-and-back on the smooth, crushed-limestone George S. Mickelson Trail through the Black Hills of South Dakota — the 33rd sanctioned 100-mile race in the country, and widely regarded as one of the best non-technical courses for a first 100-mile finish.
Hallucination 100
Six 16.6-mile figure-eight loops through the Pinckney Recreation Area, run inside the full-blown music-and-camping festival of Run Woodstock. A legitimate Western States 100 qualifier and the 4th leg of the Midwest Grand Slam of Ultrarunning, wrapped in tie-dye and peace signs.
Southeast — Georgia, Alabama, Tennessee, Arkansas
Cruel Jewel 100
Deep in the Chattahoochee National Forest of the North Georgia mountains, the Cruel Jewel piles 33,000 feet of gain onto 33,000 feet of loss across the Dragon’s Spine and back — one of the toughest, most technical 100-milers in the Southeast, and a dual Western States and Hardrock qualifier.
Bootlegger 100
Eight loops of gently rolling singletrack through Dauset Trails Nature Center and Indian Springs State Park, purpose-built as one of the most approachable first-100 courses in the Southeast — well-stocked aid every 6.25 miles, easy crew access every loop, and a Western States 100 qualifying slot.
Pinhoti 100
A point-to-point crossing of the “unmolested” Pinhoti Trail through the Talladega National Forest, over Cheaha Mountain — the highest point in Alabama — and a long-running proving ground where not every 100-mile hopeful makes it to the finish. Not a first-timer course, but very doable for the properly trained runner.
No Business 100
A single 100-plus-mile loop through the Big South Fork National River & Recreation Area, crossing the Tennessee/Kentucky state line past towering sandstone arches, rockhouses, waterfalls, and the abandoned “No Business” settlement the race is named for. The course direction reverses every year, and finishers who complete it both ways earn a special buckle.
Arkansas Traveller 100
One of the oldest 100-milers in the country — 35 runnings and counting — a 17-mile figure-eight loop followed by an 83-mile out-and-back through the Ouachita National Forest, on forest roads, jeep trails, and the blue-blazed Ouachita Trail. Often called a great first 100, backed by legendary Southern-hospitality aid station support.
Northeast & Mid-Atlantic — Vermont, Pennsylvania, Maryland, Virginia, North Carolina
Vermont 100
One of the five races that make up the Grand Slam of Ultrarunning, run every July on rolling Vermont dirt roads and horse trails since 1989. It’s also the only major American 100-miler where runners share the course with a separate, simultaneous horse endurance ride.
Eastern States 100
A 103-mile single loop circumnavigating the Pine Creek watershed in the remote Pennsylvania Wilds, with 20,000+ feet of climbing on the storied Mid State and Black Forest Trails. “Graduate-level trail running” by the race’s own description, with a finish rate that has averaged just under 50% since 2014.
Rabid Raccoon 100
Eight 12.5-mile loops of singletrack and gravel through Brady’s Run Park in western Pennsylvania, past a lake, over rolling hills, and through stream crossings. A fast-growing race that’s gone from regional favorite to an official Western States 100 qualifier in just a few years.
Oil Creek 100
Three loops of the Gerard Hiking Trail through historic Oil Creek State Park, birthplace of the world’s first commercial oil well — deep hollows, steep hillsides, and wetlands along Oil Creek, marked by over 2,000 reflective flags. “Strike oil or move on,” as the race’s own motto puts it.
C&O Canal 100
One 40-mile loop and two 30-mile loops almost entirely on the flat, packed-dirt C&O Canal towpath between Antietam and Brunswick, Maryland — minimal elevation gain, easy nighttime navigation, and a Western States 100 qualifier known for fast times.
Yeti 100
An out-and-back on the Virginia Creeper Trail, the nation’s only national scenic rail-trail, crossing more than 120 wooden trestle bridges between Abingdon and Whitetop, Virginia. Fast, crew-friendly, and widely regarded as one of the best first-100 or sub-24 courses in the country.
Massanutten Mountain Trail 100
A brutally rocky, top-heavy figure-8 through the Massanutten Mountains of Virginia’s Shenandoah Valley, with roughly 10 short but steep climbs and 18,500 feet of gain — one of the toughest, most technical 100-milers in the East, run without any official medical support.
Old Dominion 100
The East Coast’s oldest 100-miler, run every June since 1979 — a mix of pavement, gravel, singletrack, ATV trail, and stream crossings through the Massanutten and Blue Ridge mountains out of Woodstock, Virginia. Started as a runner’s alternative to a horse endurance ride, it’s been “a reason to get strong” ever since.
Grindstone 100
Widely considered the hardest 100-miler east of the 100th meridian — an out-and-back over the Allegheny Mountains’ Elliott’s Knob and Reddish Knob with roughly 21,000 feet of climbing, now run as part of the UTMB World Series with a mandatory 8-hour trail stewardship requirement for every entrant.
Umstead 100
Eight 12.5-mile loops on the wide, well-groomed multi-use trails of William B. Umstead State Park in Raleigh — purpose-built to help 50-mile runners make the leap to their first 100, with severe topography, heat, and getting lost all deliberately removed as obstacles.
Pacific Northwest — Washington
Cascade Crest 100
A clockwise loop out of Easton, Washington through the Cascade Mountains, with 30 miles on the Pacific Crest Trail, a passage through the 2.5-mile Snoqualmie Pass Tunnel, and a rope-assisted descent near the finish. One of the most demanding mountain 100-milers in the country, and a dual Western States and Hardrock qualifier.
Plain 100
“The Plain 100, Just Plain Tough.” No course markings. No aid stations. No pacers. Two unmarked loops through the Wenatchee National Forest of the eastern North Cascades, navigated entirely with a map, compass, and self-sufficiency — widely ranked among the hardest endurance races in the world.
Guides
Training, recovery, gear, and the mental side of covering 100 miles on foot.
- How to Train for Your First 100-Miler
- Recovery for Ultra Runners Over 40
- Race-Day Gear Checklist for 100-Milers
- Best Audiobooks for Ultra Training Runs
Traveling to a race on this list? Find lodging near the venue via Hotels.com.