FATMAP by Strava

The Four Pass Loop

An epic run through Colorado's Elk Mountains.

Trail Running Difficult

43 km
2.4 km
2.4 km
1 day +
Low Point
2.9 km
High Point
3.8 km
The Four Pass Loop Map

Beginning at the Maroon Snowmass Trailhead, this challenging loop crosses over four high altitude passes and provides stunning views of mountains, lakes, and open stretches of alpine meadows. The distances, elevations, and difficulty of trails vary, though overall, the whole loop is rated as strenuous.


Ambitious trail runners may complete the loop in a day, but most hikers choose to travel at a more leisurely pace and camp, completing the loop over 2-3 days. Campers should review locations of designated campsites prior to setting out. Improvised wilderness camping is also allowed in accordance with wilderness guidelines.

Starting the loop at Maroon Lake and traveling clockwise, runners will go over West Maroon Pass, Frigid Air Pass, Trail Rider Pass, and Buckskin Pass in that order. Leashed dogs may accompany their owners. The trail also allows horses, but bicycles are prohibited.

Maroon Lake to West Maroon Pass takes runners through a forest thick with aspens, an open rock field, over creeks, past Crater Lake, and over rockslides near the base of Maroon Bells. The trail continues through a valley and over West Maroon Creek (water can be high and swift—runners should check conditions beforehand and use caution). Short but steep sections of the trail will take runners into the pass.

From West Maroon Pass runners will travel on to Frigid Air Pass. This is the shortest and easiest of all the routes between passes. The trail climbs down from West Maroon pass and through open alpine meadows that offer terrific scenery and views. Frigid Air Pass opens up to panoramic views of Maroon Bells and Fravert Basin.

Frigid Air Pass then travels downhill and through a large alpine meadow which can be easily traversed with some speed, or if runners choose, they can stop and rest at campsites in the area. This trail continues on down a steep incline with close up waterfall views before continuing on through meadows and forest. The trail meets North Fork Cutoff Trail which continues steeply down and then back up, climbing to Trailrider Pass. Views from the top of the pass and on the following descent reward runners with excellent views of Snowmass Lake and the surrounding peaks.

From Trailrider Pass, runners have beautiful views as they head towards Snowmass Lake and then onto spacious Buckskin Pass. This widest pass lets runners see impressive views of the Elk Range, Snowmass Lake, Maroon Bells, and Pyramid Peak along with the possible bonus sighting of goats grazing on adjacent slopes.

The trail over Buckskin Pass descends using a series of switchbacks that wend down lush slopes carpeted in wildflowers. The trail crosses Minnehaha Gulch and another stream before returning to Maroon Lake.

Runners should note that loose boulders, unclear trails, and steep, snowy drops may create hazards along the loop. Before beginning, runners should review and take a detailed trail map and contact the Aspen Ranger District for updates on conditions, guidelines, and other helpful information.



Medium Exposure

2 out of 4

The trail contains some obstacles such as outcroppings and rock which could cause injury.


4 out of 4

In the high mountains or remote conditions, all individuals must be completely autonomous in every situation.

Best time to visit

between July and October

Similar routes nearby

Guidebooks in this area