Seth Demoor Wins Leadville Trail Marathon

The air in Leadville is thin enough to make your lungs burn, even when you’re just standing still. On Saturday, that thin air was filled with the rhythmic thud of running shoes on pavement and the heavy breathing of over 1,500 runners pushing through the historic mining district. They weren’t just running for a medal; they were racing toward Mosquito Pass, climbing to 13,185 feet — the highest point of any event in the six-race Leadville Race Series.

It was the kickoff of the summer circuit, and the stakes were high. The Trail Marathon served as a critical qualifier for the coveted Life Time Leadville Trail 100 Run. If you wanted a spot in the elite 100-mile race, you had to prove yourself here, first.

Seth Demoor knew exactly what was at stake. The Buena Vista and University of Colorado alumnus, a two-time Pikes Peak Marathon champion, crossed the finish line in 3 hours, 39 minutes, and 48 seconds. He didn’t just win; he dominated the men’s field.

“As we celebrate 25 years of owning and producing athletic events, the Leadville Trail Marathon and Heavy Half embody everything that makes endurance sports so powerful,” said Kimo Seymour, senior vice president.

Demoor’s victory wasn’t just about speed. It was about history. Two years ago, he came within seconds of breaking the course record set by his brother, Joe, in the Heavy Half. This year, he brought that same intensity to the full marathon distance. Sean Riedel of Santa Cruz, California, took second in 3:47:19, while Boulder’s Brian Condon rounded out the podium in 3:57:44.

On the women’s side, the gap was wider. Caitlin Standifer, 37, won by a full ten minutes, finishing in 4:37:51. Lea Mulligan of Tennessee took silver, and Megan Kuhnle, 28, of Boulder claimed bronze.

For the locals and the transients alike, the race was a test of endurance and elevation. The marathon gained more than 6,000 feet of climb. The Heavy Half, a 15.4-mile sprint up and back down Mosquito Pass, added another 3,400 feet of vertical gain. It’s a brutal course, and it separates the casual joggers from the serious athletes.

Locals didn’t fare poorly. Ben Boese of Gypsum, a veteran of the grueling 350-mile Unbound XL gravel race and the Leadville Trail 100, placed 13th in the marathon with a time of 4:30:25. Carrie Stafford, 47, was the top female finisher from Eagle County, placing 11th overall in 5:11:24. She’s no stranger to the grind; Stafford has completed the Lead Challenge in past years, a feat requiring athletes to complete at least five of the series' races in a single summer.

The Lead Challenge itself is a commitment. Nineteen athletes began it this year. They have to race every other event in the series, culminating in the 100 MTB and the Trail 100 Run on back-to-back weekends in August. It’s a grueling schedule that tests not just fitness, but logistics and recovery.

Nick Kierstead of Vail, a former Lead Challenge finisher, placed 26th in the marathon. Edwards residents Jason Platt, 46, and Jimmy Daly, 40, also finished in the top 35. On the Heavy Half, Nicholas Noone of Nederland won the men’s title in 2:05:13, while Paula Markel of Mammoth Lakes took the women’s title in 2:23:24. Kenzie Grant of Eagle County was the top local finisher for women, taking 28th overall in 3:19:10.

The race drew runners from 44 states and seven countries, ranging in age from 14 to 80. It speaks to the event’s reach, but also to its difficulty. You don’t just show up and win. You have to earn your place.

For the 119 athletes who began the Lead Challenge, this was just the first step. They now have to navigate the Silver Rush 50 run or bike on July 11-12, and then keep going. The road to the 100-mile race is long, and the altitude doesn’t care how fast you ran last year.

As the dust settled on Mosquito Pass, the winners celebrated, but the qualifiers were already planning their next move. The race is over, but the series is just beginning.