Aspen, Colorado

Colorado's Famous Four Pass Loop Lives Up to the Hype


, by Greg Heil

Descending Trail Rider Pass toward Snowmass Lake. Photo: Greg Heil

As I slowly crested the top of 12,420-foot Trail Rider pass, I tried to move past my fatigue and appreciate the surreal beauty of the Maroon Bells-Snowmass Wilderness. The gray rock cliffs of Snowmass Peak loomed directly above the pass, and the blue waters of Snowmass Lake sparkled in the sunlight far below. The Maroon Bells themselves could be glimpsed far to the right, but I marveled at not only how stupendous but how different the views from each of the four majestic alpine passes along this famous route are. 

The Four Pass Loop is, far and away, the most famous backpacking loop in Colorado. All four of the passes it crosses soar above 12,400 feet in elevation: West Maroon (~12,500ft), Frigid Air (~12,408ft), Trail Rider (~12,420ft), and Buckskin (~12,462ft). The spectacular ~27-mile loop circumnavigates some of Colorado's most famous mountains: the red-hued Maroon Bells. These rugged, rocky 14ers form the center of the loop, with the iconic 14ers of Pyramid Peak and Snowmass Mountain taking up flanking positions on the southeast and northwest sides of the loop. In addition to sky-scraping mountains and jagged ridgelines, crystal-clear alpine lakes such as Maroon, Crater, and Snowmass dot the loop, with a side trip to Geneva available for bonus miles.

As I studied the gray talus field below me, I thought back to the previous day when we had spent hours climbing up the rusty red dirt and rocks on the other side of the Maroon Bells. We slowly watched the soil and cliff faces change hues throughout the next day. Despite traversing a relatively concentrated area, each corner we'd turn in the steep-sided mountain valleys and each pass we'd climb over would yield a new vista. And who knows what we'd discover next—a thundering waterfall? A moose grazing in the willows next to a stream? The thrill of discovery kept us hiking!

The immensity of the landscape and the intricacies of the views threatened to overwhelm our senses. Despite having spent ample time exploring Colorado's high mountains over the past decade, three days and two nights of immersion in this epic wilderness was almost too grand—too much to process. Compared to a ho-hum everyday life spent staring at a screen and sitting surrounded by four white walls, experiencing this constant onslaught to the senses for days on end was both a challenge, and a welcome reprieve from our stifled lives of quiet desperation.

The physical challenge of the hike, the immensity of the landscape, the removal from the modern world, and surviving off solely the supplies that you carry with you on your back: these are precisely the factors that draw people to the wilderness. But unfortunately, if too many people are drawn to the same wilderness, that wilderness can be trampled into an unrecognizable mess.

A New Permit System on the Four Pass Loop

Unfortunately, the Maroon Bells and the Four Pass Loop were falling prey to their own popularity as hordes of ill-prepared visitors trampled the fragile alpine ecosystem. In 2020, the Maroon-Bells Snowmass Wilderness posted a record overnight visitation of 18,324 people entering the backcountry from the 10 most popular trailheads. According to data from the Aspen-Sopris Ranger District of the White River National Forest, this is almost double the overnight use from those same trailheads in 2010. 

The massive influx of hikers proved destructive, with camping usage in popular areas far exceeding designated sustainability thresholds. This resulted in tons of trash left along the trails, a disgusting number of unburied piles of human waste, at least 350 campsites that didn't follow Leave No Trace guidelines, and more than 1,500 illegal campfire rings, according to a proposed Wilderness overnight use plan published in advance of the implementation of the permit system. 

This spectacular Wilderness area was being loved to death. And so, after years of planning, proposals, and education, a new permit system was finally implemented at the beginning of 2023. 

Restoration in progress. Photo: Greg Heil

The new permit system requires visitors to book their backcountry camping sites and zones online in advance. The wilderness has been subdivided into different camping units, and you can apply for permits for each individual camping zone. In ultra-popular areas such as Snowmass Lake and Crater Lake, you must camp in the specific numbered site corresponding to your reservation. In other zones, you must simply camp somewhere within the designated zone while following Leave No Trace principles.

As you might imagine, permits are a hot commodity for a backpacking trip this spectacular! As my wife Christine found out while trying to book campsites within just a few minutes of permit release, some of the most popular sites (such as Snowmass Lake) can be snapped up in seconds. 

The permits are released in batches. On February 15 at 8am Mountain Time, overnight permits for April 1-July 31 are released, and on June 15 at 8am, permits for August 1-November 30 are released. On October 15, overnight permits for December 1-March 31 are released... if you fancy some winter backcountry camping by chance.

As you get ready for the permits to drop, be sure to familiarize yourself with the camping zones map to help you plan where you'd like to camp. As you get ready to book, be prepared to swap zones if your first choice of zone is taken, or even reverse the direction of your hike if you don't find your choices are working out. Christine had to try several different combinations before she secured a reasonable set of permits. We ended up camping in the East Fork and Upper Snowmass zones—two of the lesser-used areas.

Permits for trips between May 1 and October 31 will cost $10 per person per night, with a $6 processing fee on These fees will be fed back into the area as crews work to rehabilitate the high-impact campsites mentioned earlier, improve trailhead amenities, and maintain the well-used trails in the wilderness.

Finally, if you plan to hike directly from the Maroon Lake trailhead (instead of taking the shuttle bus), you'll also need to book an additional parking reservation.

The Permit System Impact... or Lack Thereof

As we hiked the Four Pass Loop, we saw obvious signs of the permit system's impact... or lake thereof. As we climbed Trail Rider Pass, we passed a large crew of workers laboring to reestablish the trail tread on the steep mountainside. This was by far the most difficult climb of the trip, and the steep, narrow trail appears to have eroded off the mountain in many places—but crews were hard at work to remedy the issue.

While it was the first time that either of us had hiked loop, we passed substantial signs of human impact on the wilderness. To abide by LNT guidelines, campsites must be at least 100 feet from the nearest trail or water source (and not in the high alpine), and even so, we passed an endless array of well-used campsites directly adjacent to the trail tread. This dramatically reduced the wilderness feel of these sections of the trail. While the Forest Service has tried to rehabilitate many of the sites, with wooden "no camping" signs posted in many places (further reducing the wilderness character), they still haven't been able to shut them all down.

We passed many people as we hiked, including playing leapfrog for the better part of two days with a group we referred to as the "beef and beers crew." At one trail junction, they offered us a snack from a massive 3-pound bag of jerky, and one of their members had affixed a beer vest to the straps of his backpack, carrying about a dozen beers for 30+ miles of hiking in the wilderness. Granted, I think most of them had been emptied fairly quickly—to save weight, of course.

Despite the number of people we passed, we never had difficulty finding camping in our permitted locations, and indeed, we had some beautiful campsites all to ourselves. But as I noted all of the rehabbed campsites and the signs of human impact that had accumulated over the years, I had a hard time imagining how choked with people this hike must have been before the permits were instituted. 

In fact, as we hiked the West Maroon trail portion of the route, we got a glimpse of the potential for trail traffic. The backcountry permits only restrict camping in the wilderness, not day hiking. Many hikers choose to complete a short 10-mile point-to-point across the mountains—either from Crested Butte to Aspen, or vice versa. The traffic was thick on this stretch of trail, with constant passing for many miles. Thankfully, once we left that area behind, the wilderness grew much more serene.

Oh, and since the backcountry permits only apply to camping, many trail runners choose to run the entire loop in a single day for a casual high alpine marathon with a meager 8,000 feet of climbing. Mind=blown.

The Hype Was High, but the Four Pass Loop Still Exceeded Expectations

Whenever you head out on a trip to a destination that's been so hyped for so many years, there's always a distinct possibility that the experience that you've been waiting for will be a letdown. As they say, Happiness = Reality - Expectation. So if your expectation is too high and reality doesn't live up to it... well, even the most epic trails can prove to be a letdown.

But as we reveled in the spectacular scenery of the Elk Range, with rugged mountain peaks soaring above us and carpets of wildflowers around us, letdown was the last thing on our minds. Every twist and turn over our 30+ miles of hiking greeted us with a new spectacular vista and a truly exceptional hiking backpacking experience. 

Really, how can you NOT have a good time when all you have to do is hike, eat, and sleep for three days in one of the most beautiful mountain ranges in the United States?!

The hype may have been high, but the Four Pass Loop still managed to dramatically exceed our expectations!

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