5 Difficult Trail Runs in Colorado

Double-digit mileage, thousands of feet in elevation gain. Thin trees, thin air. No matter your skill level, Colorado trail running ups the challenge level. These are five of our favorite Colorado trail runs, all guaranteed to leave you breathless.

Mesa Trail | Location: Boulder | Distance: 13 miles

An epic run with grand views of the Flatirons. The route essentially connects multiple trails and a couple miles of dirt roads for nearly seven miles between the Chautauqua Park trailhead (off Baseline Road) and the South Mesa trailhead (making a 13-mile out-and-back). Wind through dense ponderosa pines and grassy meadows, relishing the uphill quad and calf burn before improving footwork on quick descents. Climb about 600 feet from Chautauqua, drop 200, climb another 400 then drop a steep 800 on a dirt road to South Mesa. Take care as this one is busy on weekends.

Lower Loop to Lupine | Location: Crested Butte | Distance: 17 miles

Crested Butte’s mix of narrow and wide trail, climbs and descents, berms and rock gardens makes for a challenging and enjoyable 17-mile spin. Start at the Woods Walk trailhead on Kebler Pass Road. Run Woods Walk to Budd Trail, then connect Budd up-valley with the Upper Lower Loop; wind up the stunning Slate River Valley until crossing the river on Gunsight Bridge. Ready for the climb? Take Gunsight Connector Trail (AKA Lupine 3) uphill for about two miles before turning right down the dirt road to follow it to the original Lupine Trail. Finish the jaunt with an insane view of Mount Crested Butte.

*Go in fall to run through the changing Aspens.

**Turn around at any point for a shorter, still spectacular run; anything in the Slate River Valley is awesome.

Barr Trail | Location: Colorado Springs | Distance: 23 miles

Hit the busy Barr early or on weekdays. It’s not easy, so pat yourself on the back once reaching the top. Barr climbs 7,400 feet from Manitou Springs to the summit of Pike’s Peak (14,115 feet), making it an inspiring training venue for racers. There’s usually water in the creeks, but bring your own in drier seasons. The Pike’s Peak Marathon lures accomplished hill climbers; this year’s 60^th Anniversary (August 16^th) is sure to see exemplary talent.

Maroon Bells Four Pass Loop | Location: Aspen/Crested Butte | Distance:  28 miles

When wildflowers are in full bloom, this loop is unbeatable. Many elite distance runners rate it as their favorite day trip of all time.  Mortals take on the Four Pass Loop as a backpacking trip. Start at Crater Lake, the most photographed place in Colorado, on the Aspen side of West Maroon Pass (opposite Crested Butte). Circumnavigate counter-clockwise to connect four 12,000’+ passes: Buckskin, Trail Rider, Frigid Air and West Maroon. The entire loop is 28 miles and climbs over 8,000’. It’s also surrounded by Fourteeners: Maroon Peak (14,156’), Pyramid Peak (14,018’), Castle Peak (14,130’), North Maroon Peak (14,014’), Snowmass Mountain (14, 092’).

Turquoise Lake to Twin Lakes | Location: Leadville | Distance: 35 miles

This 35-mile stretch of the 483-mile Colorado Trail (connecting Durango to Denver) is finished by serious and prepared trail runners in one big day. Most complete it as a lightweight overnight. Schedule a drop-off/pickup or arrange a shuttle to/from Leadville. Burrowing through pine and aspen forests while crossing wet and ragged canyons, it reveals amazing views of Colorado’s two tallest Fourteeners: Mt. Massive and Mt. Elbert. On this route, the Colorado and Continental Divide Trails overlap; water flowing west off the crest heads to the Pacific while east-flowing streams are Mississippi River-bound.