Four Pass Loop

[All: 1 Avg.: 5]


27.1 Miles

Route Type

Single Loop




7,327 ft.

Highest Elevation



Just outside the mountain town of Aspen, Colorado lies one of the pinnacle trail running experiences in Colorado: The Four Pass Loop. Enveloped by flowered tundra, alpine lakes, jagged peaks, lush grasses, streams, and every color in the spectrum, this giant loop takes you for a ride, as its name claims, over four separate mountain passes.

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Four Pass Loop Walkthrough

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How to Run Four Pass Loop

Start – West Maroon Pass

The Maroon Lake trailhead near Aspen is the most common trailhead. These directions are assuming a clockwise direction if starting from Maroon Lake. This is due to easier climbing grades in this direction. After Maroon Lake there is a quick intersection. Stay right to maintain travel on the Maroon-Snowmass Trail. At about 1.7 miles you’ll reach an intersection near Crater Lake. Keep left on the West Maroon Trail.

The trail will become very rocky soon after you make the left onto West Maroon Trail, and will start a gradual climb. At about mile 3.5 the trail will cross a stream. Early in the season this could be deep and fast moving water. Caution is advised. The trail will get less rocky soon after the stream as it starts to wind through brush and willows.

As you exit the willows near treeline, the trail to the top of West Maroon Pass will be very apparent. Get ready for a steep climb with nearly 900ft in the last mile.

West Maroon Pass – Frigid Air Pass

From the saddle of West Maroon Pass, descend about 3/4 of a mile and 800ft to a fork in the trail. Head right to follow Frigid Air Pass. If you were to go left, the trail heads down the the Crested Butte area trailhead, Schofield Park. As you continue upward through the willows, there will be a sign for Frigid Air Pass near a junction by a small lake. Pass by this small lake to negotiate some switchbacks, arriving at Frigid Air Pass, 12,415ft.

Frigid Air Pass – Trail Rider Pass

Beneath Frigid Air Pass will be Fravert Basin, accessed by numerous switchbacks. This section will offer some time near the Crystal River, and some waterfalls as well. Near the river will be a fork in the trail. Stay right to cross the river, following signs to Lead King Basin. The left fork only leads to a campsite.

Once you’ve crossed the river, there will quickly be another sign. Look for the sign for Geneva Lake/Trail Rider Pass, and follow it to the right for Trail Rider Pass. You’ll soon pass a small lake, on the right, and large rock outcroppings. The trail takes a left/north turn before it begins steeply climbing up Trail Rider Pass. From the basin to the Pass, the final climb is about 700ft in less than 3/4 of a mile.

Trail Rider Pass to Buckskin Pass

Leaving Trail Rider Pass, steeply descend switchbacks and follow the trail as it takes you through the alpine far over Snowmass Lake. In about 2 miles and 1,400ft of descent, there will be a sign for Snowmass Lake and Maroon-Snowmass Trail. Take the trail for Maroon-Snowmass – though, the short trip to Snowmass Lake is well worth it. Very shortly, there is another trail split and you’ll follow signs for Buckskin Pass, signs pointing to the right. Buckskin Pass is a 1,700ft climb upward from the basin, topping out at 12,460ft.

Buckskin Pass to Maroon Lake Trailhead

Descend from Buckskin Pass on steep switchbacks. After about 3/4 mile, there is a fork in the trail. Continue heading downhill to the right. The other fork leads to Willow Pass. Continue on the same trail for approximately another 1.5 miles. You’ll be back to Crater lake at this point, and will follow the trail left to head back to the Maroon Lake trailhead, which is now about a mile ahead.

How to Train for Four Pass Loop

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