Backpacking the Four Pass Loop Trail – All You Need to Know

By: Ashley Vitiello | Last Updated on December 22, 2023

The Four Pass Loop is perhaps the most popular and highly trafficked multi-day backpacking loop in Colorado – and for a good reason. Words really can’t describe how beautiful this hike is and even though you’ll see some other people on the trail, we found that we still felt secluded enough to get in touch with ourselves and with nature. Why is it called the Four Pass Loop? Because you will summit four mountain passes, each of which surpasses 12,400 feet or higher in elevation. There’s West Maroon Pass (12,500 feet), Frigid Air Pass (12,415 feet), Trail Rider Pass (12,420 feet), and Buckskin Pass (12,500 feet). Each pass and valley offer its own unique characteristics and obstacles. Some people argue that some passes are more difficult than others, but ultimately they are all quite ambitious and should not be attempted by casual hikers. 


Distance: 27-30+ miles
Route: loop with optional side trips
Difficulty: extremely difficult
Features: mountain views, alpine lake, forests
Time of Year: July-early September

Hiking The Four Pass Loop

From the West Maroon Trailhead, it’s about 3 miles up to the loop intersection but the majority of this stretch is relatively flat compared to most of the hike. We found the most impressive wildflowers in this section, even though we were there slightly after peak time. The closer you get to the intersection, the steeper it gets and you begin your ascent to the first pass, West Maroon Pass. It’s actually a surprisingly short distance from the loop intersection to the top of West Maroon Pass, which makes for an early reward with stunning views in all directions. 

West Maroon Pass


The ascent to this pass was perhaps the shortest of all the passes, but there was still significant elevation gain. We were out of breath, especially since our packs were quiet heavy at this point. The views from this pass were the best (in my opinion) of all four passes! You can see uninterrupted vistas of the surrounding mountains and the trail in both directions. This pass was also the busiest, since lots of day hikers summit this pass from both the Crested Butte and Aspen starting points. Don’t let the amount of people scare you off; crowds cleared out significantly in the afternoon and you’ll see less and less people as the day goes on. 

The Descent

The descent from West Maroon Pass was the longest descent on the loop and it felt like we hiked down for ages. This slow descent did make for an easier time on the knees though. We planned on camping at site #0 or #1 (see below under “Camping” for the campsite map) just past Crater Lake. We didn’t make it that far and camped at site #9 at Crater Lake instead. This site was shaded and private, and was located next to a meadow that looked up at a massive waterfall coming off North Maroon Peak. We were essentially right below the Bells, which made for a stunning view of the Milky Way that night. 

Day #1 was our longest day, with over 8 miles according to All Trails (but 10 miles according to Strava GPS). Our goal was to knock out a significant amount of mileage while our legs were still fresh. Using the extended downhill to our advantage, we tried to make it as far as possible to save ourselves miles the following day. 

West Maroon Pass looking north. Left valley is the ascent from East Maroon Portal Trailhead and the right valley is the descent towards Crater Lake. 

Buckskin Pass

Leaving Crater Lake the next morning, we started the climb towards Buckskin Pass. Since this section was steep and longer than yesterday’s uphill, the day #2 ascent was quite difficult. The views were stunning, and in the bowl below the pass was a beautiful cascading waterfall. Don’t forget to turn around and look behind you to see all the views below! Perhaps the most intriguing part of Buckskin Pass is that from the top, you can see Snowmass Lake in the distance. With plans to camp at Snowmass that night, it was super cool to see our destination across the valley!

Looking southeast (Bells on right) towards our path of ascent up to Buckskin Pass.
Looking northwest towards Snowmass Lake, Snowmass Mountain, and our descent down Buckskin Pass. 

The descent down Buckskin was long and had lots of switchbacks. It was one of the easier descents because it was less rocky and more sandy than other sections of the trail. At the base of the valley, there’s a river crossing. Several stacked logs make it passable without taking boots off and it offers a nice change of scenery from the constant uphill/downhill. After the river crossing, there’s a slight ascent to Snowmass Lake. 

Snowmass Lake

We camped near campsites #13 and #14, though the sites are not numbered in person and are not very organized in this area. Basically sites #12-18 are cleared of brush and offers lots of space to set up tents. This area is very crowded so do not expect any privacy, but the views made up for it.

Snowmass Lake was easily the best feature of the entire hike. It was picture perfect, with a mirror reflection that photographers can only dream of. In the heat of the afternoon, we took a quick swim in the icy cold water. This cleanse felt like a godsend after two days of hiking in the same clothes. This experience was a great midway reset and we highly recommend taking a dip. 

At sunrise, the lake was perfectly still. You could spend hours mesmerized by the tranquil setting while pure silence embraced you. Truly an experience we’ll never forget. 

Snowmass Lake at sunrise (unedited). Photo courtesy of co-adventurer Daniel V.  

Trail Rider Pass

We had a late start on day #3 due to being brain-washed by the incredible sunrise at Snowmass Lake, but luckily the ascent to Trail Rider Pass from the lake was short and steep. We summited within a couple of hours and enjoyed breakfast at the pass. You could see Snowmass Lake below looking northeast. Looking to the west/southwest you can see multiple intersecting valleys, including the trail that accesses Geneva Lake. We opted out of this side trek and descended down the valley to the left in the picture below. 

Looking northeast from Trail Rider Pass, Snowmass Lake below.
Looking west/southwest from Trail Rider Pass. 
Waterfall in Fravert Basin. 

This is the part where things got brutal. Our initial descent from Trail Rider just was like the other passes – steep switchbacks with slippery rocks that make the going slow. The trail flattens out temporarily and you’ll pass a small lake. Once the trail starts to descend again, the fun stops. It’s very steep and has minimal functional switchbacks. There’s tons of tiny little rocks that leave you slipping all over the place unless you go 1/2 mile per hour. This portion was long and grueling, and was easily our least favorite part of the trip. The unforgiving terrain combined with the hot afternoon sun left us overheated and frustrated. We would highly recommend not being in this area in the heat of the afternoon. 

The Crossing

The light at the end of the tunnel was a large stream crossing at the bottom of the valley. We got there as fast as we could, stripped down to under garments, and sat in the cold water until we couldn’t feel our toes anymore. Combine the cold dip with fresh water and a snack break, and we were feeling much better moving forward. This stream would be very difficult to cross without just taking your shoes off and walking through knee deep water. The next mile or so is relatively flat and we soon arrived at the best waterfall on the trail. You can’t miss it!

Some steep switchbacks take you up the height of the waterfall, then the trail flattens out to a steady but smoother incline heading towards Frigid Air Pass. We aimed to hike up to the last possible camp site just below Frigid Air so we could watch the sunrise the following morning from the summit. We ended up camping at site #34, which perfectly set us up for our goal. This ascent was the most docile of all the passes, which was a relief for our last two days on the trail. 

Frigid Air Pass

Day #4 began with a dark start and packing up camp with head lamps. We took about an hour to reach the summit, just as first light was shining but the sun hadn’t risen yet. We made coffee and a dehydrated breakfast as we waited for the sunrise, and I sat in my sleeping bag for warmth. This sunrise scene was one of the highlights of the trip and was the perfect ending on our last pass. We reveled in a stunning view and the lighting was perfect during golden hour. This experience was well worth the 4:30am alarm and long hike on day #3. 

Sunrise at Frigid Air Pass. Left looking towards our ascent from the north and left looking towards our descent to the west towards Schofield Pass. You can see the peak of the Bells slightly left from center. 

Hasley Pass

After spending quite a bit of time at the top of Frigid Air Pass, we started making our way down and back towards the car. On the All Trails map, we saw a connecting route that seemed to be more efficient, which is how we inadvertently made this hike the Five Pass Loop. We had a tough time following the trail and it was significantly less established. We ended up summiting Hasley Pass, and enjoyed views in all directions. Hasley Basin had unique rock formations and allowed us to look back upon Trail Rider Pass and our less than fun descent from day #3. This view ended up being an early morning treat and a nice surprise. 

View of odd rock formations in Hasley Basin from Hasley Pass. 

Leaving Hasley Pass, the trail was quite steep and had limited switchbacks. To stay on track, we had to navigate using our downloaded All Trails Pro map. We could understand how it’s a little bit of a short cut, but we would recommend staying on the main trail unless you’re up for a little adventure. Once you get back down into the basin, it’s a relatively flat trek back to the car. We were so pooped that the trail couldn’t pass fast enough. But we made it and celebrated in the parking lot with a tequila shot.  We experienced a bit of trail magic when we found three ladies who had just finished about 30 minutes before us. They had shot glasses, lime Topo Chico, and seasonings to rim the shot glass. We shared a shot before heading into town for a big meal from a local restaurant. 

Campsite #9 at Crater Lake. 

Getting There

Aspen Start

Most hikers begin in Aspen, but this starting point can prove to be quite difficult since you cannot just drive to the trailhead. Personal drop offs are allowed before 8am, but not everyone has someone to drop them off. If you don’t have an early morning ride, you must book a ticket to ride the shuttle up from the Aspen Highlands Parking Garage. Because this shuttle services the extremely popular Maroon Bells Scenic Area, tickets can be challenging to find. Even if you can find tickets, you will end up paying a premium to park your car in the garage for several nights while you’re out adventuring. Since this is so complicated, we recommend starting from the Crested Butte side. 

Crested Butte Start

Not many people realize that you can start from the Crested Butte side by driving up Gothic Road / 317  to the East Fork / East Maroon Portal Trailhead. Drive through Mount Crested Butte on Gothic Road and just continue up towards Schofield Pass. Just a couple minutes after Schofield Pass, you’ll see a dirt parking area on the right. There’s even a bathroom at the trailhead! From Main Street, it takes about 40 minutes to get to the trailhead since it’s a dirt road with a lower speed limit. 4WD/AWD is not required, but it would definitely make the drive easier and faster. Parking is free and you can access the trailhead directly from there. It adds a minimal amount of mileage to intersect the loop from here instead of Aspen (only 2 miles longer roundtrip), and proved to be much easier for us. 


1) We encountered only one group of hikers who started the trail in Crystal. We didn’t know this was possible! But looking at the map, it does look like you can leave from Crystal or the nearby Lead King Basin Trailhead / Geneva Lake Trailhead. Crystal River Jeep Tours does drop offs at this trailhead. You can take trail #1973 (Geneva Lake) up to Geneva Lake and past it to intersect the loop, or skip Geneva Lake and follow trail #1974 (North Fork Crystal River), which will also intersect the loop. If you are considering this option, you will need to do research about leaving your car overnight in these areas because we aren’t familiar with that process. 

2) And lastly, if you’re looking to add some mileage, you can start from Snowmass Village. Use the Maroon Snowmass Trail to intersect the loop near Snowmass Lake. This route adds approximately 16 miles roundtrip (8 miles each way) but this trailhead offers free overnight parking and easy vehicle access. 

Direction, Duration & Side Trips

There’s also quite a debate about hiking this loop clockwise versus counter-clockwise. Both directions are equally difficult in their own way and it comes down to what works best for your personal experience and desires. We decided to hike counter-clockwise, which is why this trail review will be based on a CCW route.

Most hikers complete this loop in 4 days and 3 nights, which is what we did – we chose this duration so we could summit one pass per day. Depending on your ability level, you may choose a different timeframe, but we think it’s quite ambitious to complete this loop in less time. That being said, the most fit of hikers have completed it in one day and I could never imagine being able to do that! On the other hand, there’s multiple optional side trips that add more mileage if want to increase your distance. There’s Willow Lake, Geneva Lake, summiting Maroon Peak and/or North Maroon Peak, and summiting Snowmass Mountain (14,089 ft). We also encountered several people who enjoyed an extra day at Snowmass Lake. You could use this time to summit Snowmass Mountain or hike zero miles and enjoy the lake life for a day. 

What to Expect


The Forest Service has published a map of recommended camp sites along the loop. When possible, you should camp in already established sites so we can minimally impact the surrounding area. We found that most campsites had enough space for two tents and were below tree-line. This map also illustrates where you can have campfires or not, since fires aren’t allowed above 10,800 feet. Most of the campsites below 10,800 had backcountry fire rings already assembled. 

The map linked above does not show the Crater Lake campsites. They are first-come first-serve and there’s 11 of them. They’re numbered with signs along the main trail but there’s no campfires allowed at any of them. We picked #9 because of the great view, proximity to water (<1/10 mile away), and it was by itself versus the other sides were grouped in pairs. 


Late June, July, and August are the peak months to hike this trail. This allows for the best overnight temperatures and peak wildflowers! Even in the summertime, high elevation areas can experience winter weather conditions such as heavy hail and snow, as well as sub-freezing temperatures. You must beprepared for all weather conditions on this hike. During the sunny afternoon, we were over-heating in our long sleeves and pants, but the cold morning temperatures made it difficult to want to leave your sleeping bag. 

We packed our Patagonia Macro Puff jackets, as well as a beanie and a light pair of gloves. This helped a lot in the morning. Once the sun came up, we transitioned into a hiking hat with 360 degree sun protection and sunglasses. 


A common question regarding the Four Pass Loop is “how hard is it actually?” And the answer is that it’s very hard. The hike is physically and mentally demanding and pushes even the most in shape hikers to their limits. The most challenging barriers are extreme elevation gain/loss, sun exposure, severe weather (heat, cold, storms, snow, etc.), and high altitude. Do not take these factors lightly. If you do not live at altitude, you should acclimate before beginning your hike. You need to be in peak physical shape to complete the whole loop and it is not for the faint of heart. 

That being said, if you’re in shape and relatively healthy, you should be able to complete the loop. Training and preparing help keep the fun factor higher than the misery factor, which is essential to enjoying your time out there. 


A trail review I read before our hike said they were drinking about 1.5 liters each day. I don’t know if this was unrealistic or if I’m just weird, but I was drinking about 4 liters per day and still didn’t feel 100% hydrated. Keep in mind that factors such as exertion, altitude, sun exposure, and heat can dramatically increase your water intake. 

Because we were drinking so much, it was nice to have an efficient water filtration system. We use the Katadyn Gravity BeFree 3 Liter Filtration System from REI. Just fill all three liters and hang it on a tree branch with the feed going into the water storage of your choice. In a couple of minutes, we had fresh, cold water ready to go. 

I’ve assembled a rough visualization of the water availability on our hike based on each day’s route. We found that water descending West Maroon Pass and ascending Buckskin Pass was plentiful. The rest of the hike didn’t have water as frequently, so keep in mind that it’s always better to fill up whenever you see water. That way you’re always prepared for whatever is next. Use a downloaded route map to predict upcoming stream crossings, which are prime water refill spots. Don’t plan on any water being near the pass summits, so fill up in the basin below as much as possible. Take note that the streams below Frigid Air are seasonal and we found no water there in early August. Read more about treating water in the backcountry here

Day #1 – Trailhead to Crater Lake
Day #2 – Crater Lake to Snowmass Lake
Day #3 – Snowmass Lake to Fravert Basin
Day #4 – Frigid Air to Trailhead. Note that upper Fravert Basin doesn’t have any water and the streams run dry after spring melt. 


The whole area is remote enough that you may get the most spectacular view of the stars you’ve ever had. Use a moon tracking calendar to see when moon set and rise are, so you can time your star viewings while the sky is completely dark. We also used an app to plan where the Milky Way would be at what time, so we could set alarms to get out of bed for optimal viewing time. While camping near Crater Lake below the Bells, we had a perfect view of the Bells from below and the Milky Way rose from right behind them and shot across the whole sky above our camp. 10/10 would recommend getting up in the middle of the night for a sight like this. 

Milky Way above Maroon Peak. Photo courtesy of Daniel V., co-adventurer on this hike. 

Take Note

  • Bear canisters are requiredForest Service staff can and will inspect backpacker’s gear to check for proper bear storage. Do not keep food in your tent or leave it unattended. 
  • Dogs are allowed on this backpacking loop, but make sure you clean up after your furry family member. 
  • Start your hikes early and don’t summit passes in the afternoon, when pop up electrical storms are common. 
  • This trail is heavily trafficked, and is possibly going to require permits in the near future. Practice the 7 Principles of Leave No Trace so we can keep this train clean and pristine for generations to come. Especially proper disposal of human waste – make sure you’re burying waste at least 6 inches deep and 100 feet away from water sources and camps. 
  • Record the main exit and entrance points on the trail so you know where the trail allows for emergency evacuations just in case you get injured or encounter unpassable conditions. 
  • It’s best to only attempt this loop once all the snow has melted and each section of the trail is passable. Some sections were quite steep and exposed, so we can easy imagine that adding a snow pack could make the situation dangerous. 
  • Remember where you came from. The miles seem to never end and the uphill just keeps going. In the span of a few minutes, it’s easy to go from feeling like you can’t take another step to getting a second (or fiftieth) wind. Make sure you’re turning around and reflecting on how far you’ve come and appreciating how awesome you’re doing. Don’t just stare at the ground. Look up and enjoy the view. 

The Verdict

Although the Four Pass Loop was the hardest thing we’ve ever done, it was also an incredibly rewarding experience. If something like this is within your abilities, we fully recommend taking the plunge and hiking all 30 miles. You must be mentally and physically strong, but the views and seclusion are well worth the effort. Derek says he would do it again in a heartbeat. I (Ashley) had a tougher time and say I’m glad I did it, but wouldn’t do it again. To each their own I guess. Share your questions and experiences with us in the comments below – we’d love to hear from you!


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About The Author

Ashley is an adventurous soul who loves all things nature, especially warm sunshine, wildflowers, scenic snacking, and mushrooms. She is an avid outdoor enthusiast who has spent years enjoying time outside doing things like hiking, camping, and rock climbing.
Her goal with Know Nothing Nomads is to make these hobbies easily accessible through knowledgeable content and how-to's based on all the stuff she's learned on her journey. If she isn't writing an article, she's probably in a forest looking at big mountain views and tiny pieces of moss on the side of the trail.

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