In the heart of the Colorado Rockies lies an event that embodies the essence of endurance, tenacity, and the indomitable spirit of trail running – the penultimate Leadville Trail 100 Run 2026, also known as “Race Across the Sky”. The LT100 is the original event of the Leadville Race Series, featuring one hundred miles of extreme terrain that reaches 12,600 feet of elevation at Hope Pass. The course comprises forest trails and mountain roads through the Colorado Rockies and is held in San Isabel National Forest. Strambecco considers the Leadville Trail 100 Run 2026 to be one of the Best Trail Running Events in the Rockies.

The LT100 is also a Grand Slam of Ultra-Running and a Rocky Mountain Slam Series event. The Leadville Trail 100 Run takes place the weekend after its warmup event, the Leadville 10k Run, and the infamous Leadville Trail 100 MTB.

The Leadville Trail 100 Run’s origins go back to 1983 when community champions were determined to boost the local economy and celebrate the town’s mining heritage after the closure of the Climax Molybdenum Mine. This is where the idea of a grueling ultramarathon trail race was born to showcase the tenacity and indomitable spirit of the Leadville community. This challenge would forever change the world of ultramarathons, and over the years, this iconic event has grown into one of the oldest and most celebrated endurance running races globally.

The Leadville Trail 100 Run is not for the faint of heart; it’s a brutal out-and-back ultramarathon that pushes runners to their limits and beyond. The race kicks off at 4 am on Saturday. Starting at 10,200 feet, ascending to 12,600 feet, and tracing back through the stunning landscape of the Rockies, the Leadville Trail 100 Run presents a true elevation rollercoaster. The terrain varies from forest trails to mountain roads, offering a constantly changing backdrop that tests physical endurance and mental resilience. Steep climbs like Powerline, high-altitude passes such as Sugarloaf, and technical sections on the Colorado Trail characterize the route. These challenges culminate in a total elevation gain of over 18,000 feet, with the crux of the course being Hope Pass, which stands at 12,600 feet above sea level.

The course boasts 12 aid stations, each serving as a crucial pit stop where runners can refuel, rehydrate, and recharge their determination. Ten of these are fully stocked with an array of supplies, including nutrition, hydration, medical assistance, and the camaraderie of volunteers and fellow runners.

Leadville Trail 100 Run participants must be prepared to face the unpredictable nature of Colorado’s high-country weather. August in Leadville showcases a range of temperatures, with daytime highs reaching the upper 70s and nighttime lows plummeting to the upper 20s. The region’s weather can switch from sunny mornings to sudden afternoon showers, and runners might even find themselves racing through rain, hail, and snow. Hypothermia poses a significant risk due to dropping temperatures, wind, and precipitation.

For those who conquer the course in under 25 hours, a coveted “BIG” buckle awaits, an emblem of their achievement and a badge of honor earned through sheer willpower. Similarly, runners who complete the race in under 30 hours earn a “small” buckle, a testament to their dedication and grit.

Participation in the Leadville Trail 100 Run is not simply a registration matter; it’s about earning your spot on the starting line. There are several paths to securing entry: lottery, Leadville Trail 100 Run Camp + Entry Package, qualifier events (all Leadville Race Series running events serve as qualifiers), charity slots, Boundless Coaching + Entry Package, Life Time Members receive guaranteed entry, and volunteering for any Leadville Race Series event can earn runners preference in the lottery.

The Grand Slam of Ultra-Running is a series of five races representing the oldest and most prestigious 100-mile races contested in the US, including the Old Dominion 100 in Virginia, Western States 100 in California, the Vermont 100, Leadville Trail 100 in Colorado, and the Wasatch Front 100 in Utah. To complete the Rocky Mountain Slam Series, men and women have to finish four out of five annual races in the Rockies: the Bighorn 100 in Montana in June, the Hardrock 100 in Colorado in July, the Leadville Trail 100 in Colorado in August, the Wasatch Front 100 in Utah in early September and the Bear 100 in late September.