Short answer: the Leadville Trail 100 Run is 99.7 miles out and back from Leadville, Colorado, with about 15,500 ft of climb (15,492 ft on the 2026 course). The high point is Hope Pass at 12,526 ft and the low point is 9,206 ft. It starts at 4:00 AM; finish under 25 hours for the big buckle and under 30 hours to be an official finisher.
Entry is by lottery, and anyone can apply. The organizer has announced a rerouted course for 2027 with about 13,357 ft of climb, so check which course a figure refers to.
| Distance | 99.7 miles, out and back |
|---|---|
| Elevation gain | 15,492 ft (2026 course); about 13,357 ft (2027 reroute) |
| High / low point | 12,526 ft at Hope Pass / 9,206 ft |
| Start | 4:00 AM, downtown Leadville |
| Cutoffs | Big buckle under 25 hours; finisher buckle under 30 hours |
| Entry | Lottery, open to anyone who applies |
| Pacers | Allowed from Twin Lakes (about mile 40) |
Leadville Trail 100, the Race Across the Sky, runs 99.7 miles out-and-back from downtown Leadville, Colorado, with the lowest point at 9,206 ft and the highest point at 12,526 ft on Hope Pass (out and back, twice). 30-hour cutoff. Held in mid-August. The altitude is the race.
The course
The course is an out-and-back. From Leadville (10,200 ft), runners head west around Turquoise Lake, up Sugarloaf Pass (11,000 ft), down to the Fish Hatchery aid station, across the Halfmoon Creek valley, up Mount Elbert's flank toward the Twin Lakes aid station (mile 40, near the 9,206 ft low point of the course). Then up and over Hope Pass to Winfield (mile 50, the turnaround, 10,200 ft). Then everything in reverse, over Hope Pass again, back through Twin Lakes, back over Sugarloaf, and into Leadville for the finish.
Hope Pass is the iconic Leadville climb. 3,400 ft of climb over 4 miles to crest at 12,526 ft. Llamas (real ones, Leadville's pack llamas haul aid station supplies) at the top of Hope Pass aid station. The Pass is climbed both directions; the second climb (mile 60) at 4 in the afternoon is when most races are decided.
How to qualify and enter
Leadville is a lottery-entry race with two paths: the standard lottery (open to anyone, low odds), or qualification via the Leadville Race Series (top finishers at the Leadville 50, Leadville Heavy Half, Leadville Marathon, or Silver Rush 50 earn entry). The series races are held in Leadville the months prior, also at altitude.
There's a charity-bib option through the Leadville Legacy Foundation, with a fundraising minimum. Some runners use this to bypass the lottery in years when their odds are low.
Altitude: the central problem
Leadville is decided by altitude management, not vert. The course's 156 ft/mi is moderate by ultra standards. But the entire course is above 9,000 ft, with two trips above 12,000 ft. Most flatlanders need 7–14 days of acclimation before the race; some never fully acclimate and run the entire race at reduced pace.
The conventional advice: arrive in Leadville at least 4 days before the race, sleep at altitude for the entire pre-race week, and expect your race pace to be 20–30% slower than your sea-level equivalent. The pre-race acclimation is part of the race.
Gear strategy
- Vest: 8–12L. Salomon Adv Skin 12 or BD Distance 8.
- Shoes: Hoka Speedgoat 6 for the Pass, Saucony Endorphin Edge for the runnable sections, many runners change shoes at Twin Lakes (mile 40) before the Hope climb.
- Hydration: two 500ml flasks. Sodium target 700-900 mg/hr.
- Headlamp: primary + backup. The 4 AM start means dark for the first 2 hours; dark again from mile 70 to finish.
- Layers: long sleeve and beanie at Twin Lakes drop bag for the Hope Pass crossing, temperature can drop 30°F in 90 minutes as you climb.
- Poles: optional; allowed. Most fast finishers don't use them at Leadville. Hike-without-poles training pays off here.
Pacing
Pacers allowed from Twin Lakes (mile 40) onward. Most runners pick up a pacer at Twin Lakes outbound (for the Hope Pass climb) and another at Twin Lakes inbound (for the return). Some use a single pacer for both Hope crossings.
Pacing strategy: arrive at Twin Lakes (mile 40) at conservative pace. The race begins on the Hope Pass climb. Manage your effort to the top, don't redline. The descent into Winfield is technical and can wreck quads if you push it. The return over Hope is what separates buckle-finishers from drop-outs.
The Leadville feeling
Leadville has the most distinctive culture of any major American ultra. The town is small (population ~2,600), the race is the year's biggest event, and locals, many of them descendants of the silver-mining era, line the streets at 4:00 AM and again 24 hours later as runners come home. The starting line is Sixth and Harrison; the finishing chute is the same. Cross under the banner with "Race Across the Sky" overhead and you've earned the buckle.
Common questions
What is the elevation gain of the Leadville 100?
15,492 ft on the 2026 course, per the Leadville Race Series. The announced 2027 reroute is about 13,357 ft.
What are the Leadville 100 cutoff times?
Finish under 30 hours to be an official finisher and under 25 hours for the big buckle. There are also intermediate cutoffs at aid stations, including before and after Hope Pass; the runner handbook lists them.
How do you get into the Leadville 100?
Enter the lottery, which is open to anyone, during the application window the organizer posts each year. Some runners also earn entry through Leadville Race Series events or a charity bib.
What time does the Leadville 100 start?
4:00 AM, from downtown Leadville.
Sources: Leadville Race Series official Leadville Trail 100 Run page for distance, elevation, high and low points, start time, buckles and lottery. Researched, not professional coaching advice.
What these sessions assume you are measuring with
Every pace, zone and power figure here needs something recording it. These three cover running, long days and the bike.
Garmin Forerunner 965 AMOLED multisport with the training-load and threshold metrics most of these sessions assume you can see day to day.
Check price on Amazon →
COROS APEX 2 Series GPS Watch Sapphire titanium and the longest battery in its class, which is the deciding feature once a day out runs past a few hours.
Check price on Amazon →
Favero Assioma Uno Power Meter Pedal Single-sided pedal power, the cheapest honest entry into training with watts rather than estimating from heart rate.
Check price on Amazon →As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.
