Boulder
Trail Running Calendar near Boulder 2026-2027
Explore the top trail runs near Boulder for 2026-2027! We've gathered 25 exciting trail runs in the area. Check out our detailed list below to find your next local trail run.
September 2026
Experience two days of mountain endurance in Colorado with technical mountain bike and trail running races including a 50K ultra and the 100K Epic Double challenge.
October 2026
A trail race weekend in Lakewood CO offering distances from 5K to 100K on mostly singletrack dirt trails with aid stations, drop bags, and looped course formats.
A scenic 5K through Estes Park during Elk Fest with shuttle transport from the Visitor Center and a finish at Performance Park.
Trail races in Louisville CO with 5k, 10k, a new half marathon and a family Pretzel Mile plus an Oktoberfest post race festival.
Run a 4.167 mile loop every hour at 8,000 feet in this mountain endurance race where the last person standing wins a 1,000 dollar prize.
Fundraising run at Red Rocks Park and Amphitheatre on October 11, 2026, supporting lung disease education, advocacy and research in Colorado.
Traditional Backyard Ultra at Luvin Arms Animal Sanctuary in Erie, CO with repeated 4.167 mile loops on mostly flat off road terrain, on site camps, and rescued animals.
MonsterDASH Louisville on Oct 25, 2026 offers a new half marathon plus 5k, 10k and a kids mile with costume contests, expo, and themed runner perks.
Backyard ultra at Bear Creek Lake Park where runners repeat a 4.16-mile loop each hour until one remains or the field is stopped at the 11th hour.
November 2026
Trail races on November 14, 2026 in Louisville CO offering Half Marathon, 10K and 5K on dirt out and back courses with aid stations and post-race festivities.
Trail races in Loveland, CO offering a roughly 13-mile half marathon with a 5-hour limit and a shorter 5K on varied, mixed-terrain trails.
A self-supported 50K in Golden, Colorado visiting four local peaks with Parfet Park as the central hub and minimal course markings.
December 2026
A mountain challenge in Estes Park where runners complete 2km laps with 540ft of gain to reach elevation milestones and collect poker chips for rank.
Holiday trail runs in Louisville CO with 5k, 10k, a new half marathon, expo pickup, giveaways, family activities, and a visit from Santa.
Celebrate the season with a festive 10K featuring 1,500 feet of climbing and beautiful trail views at the YMCA of the Rockies.
February 2027
May 2027
Trail races at YMCA of the Rockies on May 22, 2027 offering 10K, 25K, and 50K on mostly runnable singletrack at 8,000 feet; the 50K includes 6,000 feet of gain.