Trip Overview: The Four Pass Loop in the Maroon Bells-Snowmass Wilderness is one of the premiere backpacking loops in Colorado. At 28 miles in length, this loop is typically hiked over the course of 3 to 5 days depending on your fitness level. During the trek you hike over four high elevation mountain passes, reach a peak altitude of ~12,500 feet, and climb nearly 9,000 feet of elevation. Highlights of the Four Pass Loop include epic views of the Maroon Bells and several nearby mountain peaks, expansive views from atop mountain passes, summer wildflower blooms, and views of alpine lakes and idyllic rivers. The majority of the images are from a trip that took place in early August.
- Overall map of the Four Pass Loop in the Maroon Bells-Snowmass Wilderness (PDF)
- Link to purchase a topographic map of the Maroon Bells area (here)
Jump to Day 1 hike – Maroon Lake Trailhead to West Maroon Pass
Jump to Day 2 hike – West Maroon Pass to North Fork
Jump to Day 3 hike – North Fork to Snowmass Lake
Jump to Day 4 hike – Snowmass Lake to Maroon Lake Trailhead
Permits: To backpack and camp within the Maroon Bells-Snowmass Wilderness, you must self-register and fill out a permit at the trailhead before starting your hike. There is currently (as of 2019) no quota on the number of hikers allowed to start the Four Pass Loop each day, so no advanced reservations are required. Note that group sizes are currently limited to 10 hikers. Because there is no permit quota system and the trail is very scenic, expect there to be some crowds during the peak summer hiking season. If you are looking for more solitude, consider hiking the Four Pass Loop earlier or later in the hiking season or hike mid week instead of on the weekend.
Due to the popularity of the Maroon Bells area, it is very important to follow all regulations. Backpackers are required to store food and scented items in bear resistant canisters. Furthermore, all human waste must either be packed out in human waste (WAG) bags or must be properly buried. Lastly, there are some campfire regulations that prohibit fires near Crater Lake and any above 10,800 feet of elevation. A trail guide listing all regulations provided by the Forest Service can be found here.
Also, note that a permit quota system for the Four Pass Loop may be implemented starting in the summer 2020 hiking season (Aspen Times article). Backpackers planning to visit in 2020, should keep an eye on the Forest Service website to see if permits need to be reserved.
Logistics: The Maroon Lake trailhead is about a 40 minute drive southwest from Aspen, CO. Near the trailhead there is a parking area reserved for overnight backpackers (you must pay a $10 fee if you drive a private vehicle here). Note that the number of parking spots in the overnight lot is very limited. If the lot is full upon arrival, you will be forced to turn back and use the shuttle bus. If you are lucky enough to get a parking spot in the overnight lot, you can stay for up to 5 days. Also, note that traffic on the road to Maroon Lake Trailhead is restricted between 8am – 5pm. If you plan to drive yourself to the trailhead and park there, you should arrive before 8am.
By far the easiest way to access Maroon Bells is to take the Maroon Bells shuttle , which costs $8 per adult (more info here). The shuttle service service that operates between 8am-5pm from June to October leaves from the Aspen Highlands Ski Area.
If you are visiting Colorado from a lower elevation state, it is recommended to spend a couple days acclimating to the elevation before starting your trek. Whether you stay in Denver or Aspen (or somewhere else) is up to you, but acclimating will help prepare you for the hike. The Four Pass Loop starts at roughly 9,500 feet so the air is fairly thin at the trailhead.
The Four Pass Loop can be hiked in either the clockwise or counter clockwise directions. In this report, we describe the clockwise route. I prefer this route because you can hike a relatively easy 6 mile first day where you do not need to cross any mountain passes. If you plan to hike further on your first day and will hike over a mountain pass, you should plan to begin hiking quite early in the morning. Afternoon thunderstorms are common in the Colorado Rockies, and you do not want want to be exposed atop a pass in the afternoon when storms frequently roll in.
Supplies: There are black bears in the park, so you are required to bring a bear canister. I also recommend pre-treating your hiking clothes and tent with permethrin spray repellent. This repellent keeps mosquitoes, flies, and ticks away. The permethrin treatment stays on your clothes for up to 7 washes, so it helps reduce the amount of spray you need to put on your skin.
The temperature can be quite cold at the higher elevation campsites in the evening and mornings. I highly recommend having some warm wool-based clothes for camp. Wool is great because it doesn’t pick up funky stenches as fast at cotton or synthetic clothes and also because it dries out quickly if you get caught in the rain. You also want to make sure your hiking clothes are made of synthetic (or wool) fabric that will dry out if you get caught by a thunderstorm and get wet. That last thing you want is to be drenched in cotton clothes that will stay wet and keep you cold.
Below is a list of recommended gear for the Four Pass Loop:
- a lightweight hiking rain jacket (North Face Venture 2 Jacket)
- fast drying synthetic hiking pants (prAna Zion Pants)
- a quick drying long sleeve hiking shirt (Columbia Silver Ridge L/S Shirt)
- wool outer socks (People Socks Moreno 4-pack)
- thin blister preventing base socks (WrightSock double layer Coolmesh)
- quick drying synthetic boxer briefs (ExOfficio Give-N-Go)
- light bandana for sun protection (Levi’s printed bandana)
- mesh back trucker hat (Patagonia LoPro Trucker Hat)
- adjustable fabric belt (Bison designs belt)
- Gore-tex hiking shoes (adidas Outdoor Terrex Fast R Gore-Tex Shoe)
Clothes for camp
- wool leggings (Minus33 Merino Wool Kancamagus Midweight Bottom)
- wool base layer shirt (Minus33 Merino Wool Chocorua Midweight Crew)
- warm wool overshirt (Pendleton Long Sleeve Classic-Fit Board Shirt)
- lightweight down jacket (Patagonia 800-fill Down Jacket)
- lightweight camp shoes (Xero Z-Trail lightweight sandal)
- warm beanie hat and thin pair of gloves
- topographic map (Maroon Bells topo map)
- trekking poles (Cascade Mountain Tech Carbon Fiber Trekking Poles)
- 3 liter hydration bladder (Camelbak Antidote Reservoir)
- 65 liter backpack (Osprey Atmos 65 Liter pack)
- water filtration system (Sawyer Squeeze water filtration system)
- strong tent with rain-fly (Alps Mountaineering Chaos 2 Tent)
- inflatable sleeping pad (REI Co-op AirRail 1.5 Self-Inflating Sleeping Pad)
- sleeping bag (The North Face Furnace 20 degree Sleeping Bag)
- lightweight backpacking chair (Therm-a-Rest trekker chair)
- lightweight lantern (MPOWERD Luci Outdoor 2.0)
- headlamp (Black Diamond Storm Headlamp)
- multi-tool with knife (Gerber MP400 compact multi-plier)
- bear canister (BearVault BV500)
- lightweight stove (MSR PocketRocket 2)
- lighter (BIC plastic lighters)
- 2 liter pot (GSI Outdoors Halulite Boiler Pot)
- coffee cup (GSI Outdoors Glacier Stainless Cup)
- lightweight spork (Snow Peak Titanium Spork)
- small, quick drying towel (REI mutli towel lite)
- wet wipes (Stall Mates individually wrapped wipes)
- mole skin for blisters (Spenco 2nd Skin Adhesive)
- small amount of duct tape for gear repairs
- chapstick and sun screen
Food and drink
- a variety of my favorite dehydrated meals
- electrolyte replacement (NUUN Hydration Tablets)
- quick snacks (Clif Shot Bloks and Clif energy bars)
- instant coffee (Starbucks VIA)
Difficulty and Weather: The Four Pass Loop is very popular so the trail is well marked. There is little risk to get lost or be stranded. The primary risks are altitude sickness, lightning strikes, and exhaustion. To mitigate theses risks hikers should acclimate to the altitude before setting off on their trek. You should also remember that this is a strenuous hike with lots of elevation gain. If you are not used to backpacking at high altitude, plan to complete the trek over 4 to 5 days rather than 3. Furthermore, hikers should avoid getting stuck on any of the four mountain passes during the late afternoon when thunderstorms are frequent. Plan to cross passes in the morning and keep a keen eye out for storm clouds. If there is a storm rolling in, plan to seek shelter at a lower elevation and hike over the pass later after the storm has rolled through.
The rest of the risks are fairly typical for backpacking in the mountains. Hike within your fitness and skill level and be cautious at river and stream crossings. Also, be sure to filter all water before drinking.
Day 1: 6 miles; +2,530 / -440 feet; Maroon Lake Trailhead to West Maroon Pass
The itinerary described in this report tackles the Four Pass Loop over four days. The hikes on any given day are between 6 and 9 miles long. If you plan to hike the loop in more or fewer days, you can use this guide from the Forest Service to decide where to camp. Note that there is a lot of elevation gain, so only very fit backpackers should tackle this loop in fewer than 4 days.
On day 1 of the clockwise itinerary, you start the hike at the Maroon Lake Trailhead. There are vault toilets at the trailhead, but there is not potable water access. Plan to fill your hydration bladders before arriving or filter water from near Maroon Lake. The loop starts by following the Maroon Snowmass Trail (#1975) along the north shore of Maroon Lake. Along this stretch of the hike you are treat to the famous view of Maroon Lake with the Maroon Bells in the background.
After roughly 1.7 miles, you reach a junction near Crater Lake. Take a left and proceed south onto the West Maroon Trail (#1970), which heads to West Maroon Pass. This trail meanders along the shore of Crater Lake and then heads up into the valley that Maroon Creek runs through. After about the three mile mark you will reach some of the first campsites. I suggest pushing up to the ~6 mile mark and making camp about mile from West Maroon Pass. The views in the this area are great and you can then rest after a short first day.
Day 2: 7 miles; +1,660 / -2,900 feet; West Maroon Pass to North Fork of Crystal River
On day 2 of the Four Pass Loop, you climb up over West Maroon Pass and Frigid Air Pass. Both passes provide great views and you have plenty of time to relax and take photos since the hike is only 7 miles long.
The hike starts with a 1 mile, ~850 foot climb to the top of West Maroon Pass. From there, the next two miles traverse along a ridge leading towards Frigid Air Pass. At the ~3 mile mark, you reach a junction. At this point you transition onto the Fravert Basin Trail (#1974). Take a right at the junction and head north to the top of Frigid Air Pass (about a 400 foot climb from the junction). At the top of Frigid Air Pass you get great views of the Fravert Basin and of the backside of the Maroon Bells. The trail then heads north and descends into the Fravert Basin. You drop some 2,000 feet over the next 3 miles. Starting at about the 5 mile mark, there are several campsites along the trail. The campsite in this itinerary is near a couple small pools of water near the 6.5 mile mark.
Day 3: 6.5 miles; +2,540 / -2,010 feet; North Fork of Crystal River to Snowmass Lake
The Day 3 hike is just over 6 miles long and includes a hike over Trail Rider Pass. The trail starts with a flat ~1.5 mile hike northwest along the Fravert Basin Trail (#1974). There are continued nice views of the valley and North Fork of the Crystal River along the trail. At the ~1.5 mile mark, you reach a junction. Take a right at the junction and follow the North Cutoff Trail (#1976) northwest up the ridge towards Trail Rider Pass. Roughly a mile into the climb, you will reach a stream and another trail junction. Follow the trail going to the right which meanders via switchbacks north along the stream.
Around the 3 mile mark, this trail meets up with the Geneva Lake Trail (#1973). Take the Geneva Lakes Trail to the east towards Trail Rider Pass and Snowmass Lake. From the junction it is a ~1.2 mile hike to the top of Trail Rider Pass. From the top of the pass you get great views of Snowmass Lake and the surrounding area. After a rest, you then descend down to Snowmass Lake. It is a ~2 mile hike down to the lake. Near the lake, there is a junction. Take the route to the left, which heads towards the shore of Snowmass Lake. This trail leads to a stream crossing and there are several campsites in the area past the stream.
Day 4: 8.5 miles; +2,180 / -3,560 feet; Snowmass Lake to Maroon Lake Trailhead
On Day 4 you hike 8.5 miles from Snowmass Lake back to the Maroon Lakes Trailhead. This is the longest hike in this itinerary, but your packs should be a bit lighter on that last day since you have eaten most of your food! Start the hike by crossing to the north side of the stream that flows from the east side of Snowmass Lake (you may have already crossed yesterday). Roughly a quarter mile northeast of the stream crossing, you reach a junction with the Maroon Snowmass Trail (#1975). Take the Maroon Snowmass Trail southeast towards Buckskin Pass. Around the 2 mile mark the trail begins to steadily climb up to Buckskin Pass. After climbing ~1,700 feet, you reach the top of the pass at the 4 mile mark. There are some great views near Buckskin Pass, so this makes for a good lunch spot. From here, you just continue east along the Maroon Snowmass Trail as it descends nearly 3,000 feet down to the trailhead.
Here are some related trip reports: