Turquoise lakes, kaleidoscopic wildflowers, bursting waterfalls, plush singletrack trails and endless alpine vistas. If these are qualities you seek in a mountain run, then Colorado’s Four Pass Loop (4PL), a classic adventure running linkup through the jagged Elk Mountains just south of Aspen, is one for your bucket list.
The route entails 27 miles of singletrack trails and 8,000 feet of elevation gain as it circles some of the most photographed peaks in North America. For trail runners who wish to tackle it in a day, it’s a robust but enjoyable high-altitude endurance test piece.
I first ran it solo two summers ago, and it’s so special that I had to go back again, this time joined by friend and frequent adventure partner Brian Metzler, Competitor’s editor in chief. Click through the photos below to see how our amazing day went down and check out this map of the route.
Early Morning Start
We started just after sunrise at Maroon Lake, as several nature photographers line up behind us to capture first light on the Maroon Bells. The main Maroon Bells trailhead is located 10 miles south of Aspen up Maroon Creek Road. If you're planning to drive, arrive early as the road is only open to buses from 8 a.m. to 5 p.m.
Crossing Maroon Creek
Beginning with this creek crossing en route to West Maroon Pass, we couldn’t have been happier with our shoe choice. We were both rocking the new Hoka One Tor Speed 2 mid-top, which boasts maximum cushion, grippy Vibram outsoles, waterproof eVENT membrane, and stability that allows you to run right over small rocks and roots for hours. For a long day on the trail, it offered plenty of long-wearing comfort, soft cushioning, reliable traction, midfoot and high-ankle support and waterproof/breathable protection
West Maroon Pass
With 3,000 feet of climbing over 7 miles, this is the biggest—but not toughest—climb of the day. We paced ourselves early and felt great.
Heading Up Frigid Air Pass
Two down, two to go! This is a south-looking view of Brian punching it to the summit of Frigid Air Pass. Entranced by the explosive wildflowers surrounding pristine singetrack trails, we barely noticed the 2.5 miles and easy elevation change between West Maroon and Frigid Air passes. Off in the distance, there's a trail that leads south to Crested Butte, which is only about 20 miles away.
Over Frigid Air Pass
Here we’re heading off the north side of Frigid Air Pass into the verdant green Fravert Basin, with 14,163-foot Maroon Peak presiding. Though high pressure inspired confidence, alpine weather can be dangerously fickle. As insurance, I carried a practically weight-less Outdoor Research Helium II jacket, along with a Buff, some arm sleeves, and a pair of light gloves.
Cruising through the sublime Fravert Basin. If forced to choose, I’d call this my favorite section of 4PL. Yep…I’m gonna run the 4PL every year for as long as I can.
The Final Climb to Trail Rider Pass
This is the last push up Trail Rider Pass. During this climb, which delivers the steepest, most demanding sections of the route, the exertion, sun and altitude began to take a toll. I’ve learned the hard way about the importance of keeping electrolytes in balance, so I augmented Honey Stinger gels, chews, and waffles with Skratch Labs Rescue Hydration mix. With sodium levels replenished, I felt better right away.
Ascent to Trail Rider Pass
Beginning the steep descent down Trail Rider Pass toward picturesque and pristine Snowmass Lake.
Usage of Maroon-Bells-Snowmass Wilderness has spiked in recent years, with Four Pass Loop being a top attraction. Snowmass Lake is a particularly powerful magnet for backpackers, runners and hikers, and is in danger of being loved to death. Prevalent impact issues that pose a threat to this sensitive environment include litter, unburied human feces, and bear encounters due to improper food storage. Please treat Wilderness with the respect it deserves, and leave only your footprints behind you.
Approach to Bucksin Pass
The jagged westerly aspect of the Maroon Bells gets closer as we begin the last climb up Buckskin Pass.
While ascending Buckskin Pass, we turned back to gawk at this view of Snowmass Mountain (14,098 feet).
Going Over Buckskin Pass
Yeah, baby! With the majestic Pyramid Peak (14,026 feet) in the foreground, we’re home free over Buckskin Pass.
We made it back to where we started unscathed, although the heat and fatigue certainly became a factor. We took a dip in Maroon Lake and celebrated with a cold beer. We finished in 9 hours, a much more leisurely clip than Sage Canaday’s blistering 4:27 FKT set in 2013. No matter what pace you go, it's all about enjoying the time on the trail and the scenery.