Trail Running calendar near Larkspur 2025-2026

The Sawatch Ascent 50k is a challenging high-alpine trail race held in Nathrop, Colorado, showcasing the stunning Sawatch Range. Covering 33 miles with 7,000 feet of vertical gain, the course features a mix of 26 miles of singletrack, paved, and gravel roads, including 12 miles on the Colorado Trail..

14er Fest is a fall trail-running event in Buena Vista, Colorado, featuring two races: an 8.7-mile (14K) course and a 3.1-mile (5K) course. The 14K starts in Buena Vista River Park, crosses the Arkansas River, and climbs the Midland Hill Trail System for over 500 feet of elevation gain, offering pan..

The Rim to Rim Royal Gorge Races, held in Canon City, Colorado, offer a scenic and challenging running experience featuring three main events: a 5K road run, an 8-mile trail run, and a half marathon trail run. Each race includes the unique opportunity to cross the iconic Royal Gorge Bridge, the high..

Castle Rock Trail Festival / liveBIG Run invites runners of all levels to explore Castle Rock’s ridgeline trails, including Philip S. Miller Park and Ridgeline Open Space, on Saturday, Oct. 4.Distances include a liveBIG Family Adventure Run (a family-friendly obstacle course), 5K, 10K, Ridgeline Tra..

The Above the Clouds Ultra is an annual trail running event held in Woodland Park, Colorado, known as the "City Above the Clouds." It features two race distances: a 50K ultra and a 10K run. The course showcases stunning Colorado fall colors and offers fast, flowing singletrack trails around Rampart..

The Bear Chase Race Endurance Festival unfolds at Bear Creek Lake Park in Lakewood, Colorado, and offers six races: 100K, 50 Mile, 50K, Half Marathon, 10K, and 5K (with a Baby Bear 10K variant). The mostly dirt, single-track course is described as fast by trail standards and not overly technical, wi..

Suffer Better Fall Trail Runs take place at Staunton State Park, just off Highway 285 near Conifer, Colorado. The event offers four distances: 50K, 25K, a 25K FishSlappers edition, and a new 5K. The course showcases CO’s best trails—lovely, flowing singletrack with significant vertical gain (roughly..

Boulder XC Series Meet 1 is a family-friendly cross-country event held at Valmont City Park (South) in Boulder, Colorado (5110 Valmont Rd). The meet offers three distances: 1K for younger runners, 3K for those up to 16, and a 5K open race, welcoming participants of all ages and abilities. It’s the f..

The Great Trailhead Foot Race 10 Miler takes place at Bear Creek Lake Park in Lakewood, Colorado, offering runners a scenic trail experience with single-track dirt paths against the backdrop of Denver’s skyline. Participants can choose between a 5-mile or a challenging 10-mile double-lap course. Reg..

Indian Creek Trail Runs, the oldest official race in the Human Potential Running Series, is the Fall Classic held at Indian Creek Campground in Sedalia, CO near Denver. Events include 50-Mile, 55k, 15-Mile, and 5-Mile on single-track trails through Front Range montane habitats—from lodgepole pine fo..

Bobcat Trail Race is held in Palmer Park, Colorado Springs, featuring four distances: 50K, 25K, 10K, and 5K. Runners traverse trails with panoramic city views and a Pikes Peak backdrop, through rocky bluffs, forests, and technical single-track. The 50K covers about 31 miles with roughly 3,700 ft of..

Bridge Burner Ultra is a scenic, late-season race based in Canon City, Colorado, offering multiple distances: 35 miles, 50K, 35K, and 10K. The single-loop course runs along the Arkansas River, through historic Tunnel Drive tunnels, and climbs to 7,109 feet for sweeping views of the Royal Gorge, Sang..

Beware The Bear Trail Races take place at Bear Creek Lake Park in Lakewood, Colorado. The event offers four distances: 5K, 15K, a 5K+15K double, and a Kids 1K race. The courses are mostly dirt, using single and double-track trails with short, steep climbs, rollers, and rugged terrain, providing a so..

The Colleen De Reuck XC Classic is a cross country running event held annually at Harlow Platts Community Park in Boulder, Colorado. Honoring renowned distance runner Colleen De Reuck, the race promotes health, fitness, and celebrates local Olympians, with 2025 honoring 2012 Olympic marathoner Yoshi..

The HRCA Backcountry Wilderness Half Marathon is an annual 13.1-mile trail race held in Highlands Ranch, Colorado, featuring a scenic single-loop course through the Douglas County East/West trail and the Backcountry Wilderness Area. The race offers a challenging route on dirt, gravel, and singletrac..

Bingo! Trail Party, hosted by the Human Potential Running Series, takes place at May Farms in Byers, Colorado. It features five levels: Level 1 (6–10 miles), Level 2 (8–20 miles), Level 3 (10–42 miles), Level 4 (10–54 miles), and Level 5 (18–54 miles), with a 9 PM time limit and a 300-runner cap. Th..

Louisville Trail Race in Louisville, Colorado offers Half Marathon (13.1 miles), 10K (6.2 miles), and 5K (3.1 miles) on mostly dirt trails through the Front Range backdrop near the Flat Irons. The mostly flat to gently rolling course features two notable climbs and panoramic views of the Front Range..

Colorado Cold Rush Ultra, held in Colorado Springs, offers 50K, half marathon, and 10K options. The race is billed as the "coolest" winter running event and features a route starting at Bear Creek Regional Park, climbing High Drive, and threading through tunnels from the Colorado gold rush along Gol..

The Sawmill Trail Runs is an annual trail running event held at Staunton State Park in Pine, Colorado, approximately 40 miles southwest of Denver. The race offers three distance options: 8-Mile, 16-Mile, and 50k, with a combined runner capacity of 250. The course features scenic and challenging terr..

Stories Trail Runs is a winter trail racing festival at Cheyenne Mountain State Park in Colorado Springs, CO, offering a scenic, community-focused atmosphere with views of Cheyenne Mountain, Pike’s Peak, and the Front Range. The weekend includes 6-Hour and 15-Hour timed events, plus traditional 10k,..