Leadville Trail 100 — The Race Across the Sky
The Race That Made 100 Miles Famous
Before Leadville, 100-mile trail races were obscure. After Leadville, they were aspirational. Running since 1983, this race has done more to bring runners into ultramarathoning than any other event in history.
It starts and ends in Leadville, Colorado — the highest incorporated city in the United States at 10,200 feet. Every single mile of this course sits above 9,200 feet. The high point is Hope Pass at 12,600 feet, which runners cross twice — once going out, once coming back.
The race is known as The Race Across the Sky. That phrase is accurate.
The Course
Leadville is an out-and-back. Runners leave Leadville, run 50 miles to the turnaround at Winfield, then run 50 miles back.
Hope Pass Outbound (Miles 39-45): The defining section. A 3,000-foot climb over 3.5 miles to the 12,600-foot summit. Steep, loose, relentless. Llamas carry supplies for the aid station at the top. Runners arriving here in good shape feel the race is winnable. Those arriving broken know the day will get very long.
Winfield (Mile 50): The turnaround. How a runner looks here is the most reliable predictor of whether they finish.
Hope Pass Return (Miles 55-61): The same climb in reverse. A 3,000-foot climb on legs that have run 55 miles at altitude. Widely considered one of the hardest single sections in American ultrarunning.
Twin Lakes (Mile 60): The critical aid station. Runners have a firm cutoff here. This is where crews make the call — are they finishing, or is it over?
The Buckle System
Sub-25 hours earns a silver buckle. Sub-30 earns bronze. Cutoff is 30 hours. The silver buckle is one of the most coveted finish awards in American ultrarunning.
Mike McCalley’s Race
Mike McCalley crossed the Leadville finish line in 2025 at age 54, two years after he couldn’t run a quarter mile. He ran with a fever from the start, made eight bathroom stops in the first half, vomited at mile 80, and nearly missed cutoffs after leaving his poles at Winfield and backtracking up the mountain to get them.
His crew brought him back at Twin Lakes when he sat in the chair. His wife got in the mess with him. He left. He finished. He jumped at the line.
That’s what Leadville produces.
100 miles | 15,600 ft gain | Base: 10,200 ft | High point: Hope Pass 12,600 ft | Mid-August | Start/Finish: Leadville, CO