About the race
The Leadville Trail 100 MTB is a 100-mile mountain bike race held in and around Leadville, Colorado, at more than 10,000 feet above sea level. It is part of the Leadville Race Series and is known by the nickname LT100.
History
The race grew out of the Leadville Trail 100 foot race. Ken Chlouber started both to help the town's economy after the Climax Mine closed, and the bike race was the idea of Tony Post, then a marketing executive at Rockport. The first running in 1994 attracted about 150 entrants, and in 2019 there were 1,644 racers. Life Time bought the event in 2010, and it joined the Life Time Grand Prix in 2022. The wider Leadville Race Series dates back to 1983, when 45 runners set out on the original 100-mile run.
The course
It is an out-and-back route of about 50 miles each way, starting and finishing in downtown Leadville at roughly 10,200 feet. Five big climbs define the day: St Kevins, Sugarloaf, Columbine, Powerline and Turquoise Lake Road. Columbine is the largest, gaining more than 3,000 feet to a high point above 12,500 feet at the Columbine Mine, which is the halfway turnaround. Six aid stations are used, several of them visited twice. The course was changed in 2026 to deal with wildfire damage, which cut about 3,000 feet of climbing.
Distances
The race is billed as 100 miles, although Wikipedia puts the true length nearer 104 miles. Total climbing is about 11,000 feet.
Cut-offs and entry basics
Riders must leave each aid station before its cut-off time, or their race ends with a DNF. On the final leg, finishing in under nine hours earns the "big buckle", and under twelve the "small buckle"; both were trimmed by 45 minutes in 2026 because of the course change. Entry is restricted, with a random lottery, which the organiser says opens on 1 December, plus places awarded through qualifying events, charity entries and training camps. The organiser also has pages on official rules and deferral policies.
Where to watch
The start and finish are in downtown Leadville. Beyond that, check the organiser for spectator locations. The Twin Lakes aid station and Columbine Mine appear on the route.
Weather
Leadville is a high-altitude mountain town, and August days there are typically summer-like, though storms can build over the peaks and the air is thin. This is general background, not a forecast.
SourcesLeadville Race Series home · Wikipedia: Leadville Trail 100 MTB