Boulder
Trail Running Calendar near Boulder 2026-2027
Explore the top trail runs near Boulder for 2026-2027! We've gathered 22 exciting trail runs in the area. Check out our detailed list below to find your next local trail run.
August 2026
A mostly dirt and trail race along Boulder Reservoir in Boulder, Colorado, with about 200 feet of elevation gain. Distances range from a 10K to a full marathon, plus a relay option.
Westminster Trail Races on August 15 2026 offers multiple trail distances around Standley Lake on packed dirt with lake and mountain views.
Trail-based chip timed half marathon and 5K near Fraser, Colorado, on unpaved roads and trails, with aid stations and proceeds supporting the Shining Stars Foundation.
Run Like the Wind in Allenspark on August 29, 2026 features a 5K race, a 2K run/walk and a dog jog option. Proceeds benefit The Old Gallery and participating dogs are entered in an amateur dog show.
September 2026
A multi day ultra on a 2 mile loop in Loveland offering time based and distance races with round the clock aid and on site camping.
Join the community for a 5K run or walk on a brand new dirt course at the North Arvada Middle School Athletic Complex. Support local high school racers before taking on this off road route yourself.
Multi distance endurance event in Longmont, Colorado on September 11 12 2026, held on a flat 1.05 mile loop with in person and virtual options.
A two-day trail and bike event in Estes Park featuring 31-mile bike and run options, a 15-mile heavy half, and a 62-mile duathlon, with rugged trails, significant climbs, and aid stations supporting competitors.
October 2026
A weekend of looped trail races at Bear Creek Lake Park near Lakewood CO offering 100K, 50 Mile, 50K, half marathon, 10K and 5K on mostly singletrack dirt.
A scenic 5K through Estes Park during Elk Fest with shuttle transport from the Visitor Center and a finish at Performance Park.
A mountain backyard ultra in Estes Park with 4.167-mile loops every hour on trails beside Rocky Mountain National Park; last runner standing wins $1,000.
Run the Rocks at Red Rocks Park in Morrison, CO offers a 5k and a 1.3-mile family course, raising funds for lung disease education, advocacy and research in Colorado.
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.