Leadville Trail 100 — the Race Across the Sky — runs 100 miles out-and-back from downtown Leadville, Colorado, with the lowest point at 9,200 ft and the highest point at 12,600 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, 9,200 ft, the lowest point on 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 12,600 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.

By the numbers

  • Distance: 100 miles
  • Vert gain: 15,600 ft
  • Vert per mile: 156 ft/mi (moderate)
  • Lowest point: 9,200 ft (Twin Lakes)
  • Highest point: 12,600 ft (Hope Pass)
  • Cutoff: 30 hours
  • Sub-25 buckle: Big silver buckle
  • Sub-30 buckle: Standard finisher buckle
  • Date: Mid-August (Saturday start, 4:00 AM)

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.