How to Hike the Four Pass Loop in the Maroon Bells

The Four Pass Loop in the Maroon Bells is one of the most iconic and visually stunning backpacking routes in the entire Rocky Mountain region. Located within the Maroon Bells-Snowmass Wilderness of Colorado’s White River National Forest, this 26- to 28-mile loop traverses four high-altitude mountain passes—Maroon Pass, West Maroon Pass, Frigid Air Pass, and Buckskin Pass—each offering panoramic views of jagged peaks, alpine lakes, and wildflower-strewn meadows. The route circles the legendary Maroon Bells, two of the most photographed mountains in North America, and weaves through some of the most pristine backcountry terrain in the United States.

For experienced hikers and seasoned backpackers, the Four Pass Loop is not just a trek—it’s a rite of passage. It demands physical endurance, careful planning, and respect for high-altitude environments. Yet for those who complete it, the rewards are immeasurable: solitude among ancient peaks, crystal-clear alpine lakes reflecting snow-capped summits, and the profound satisfaction of navigating one of the most challenging and beautiful loops in the American West.

This guide provides a comprehensive, step-by-step roadmap to successfully hiking the Four Pass Loop. Whether you’re a seasoned mountaineer or an ambitious day-hiker ready to take on a multi-day adventure, this tutorial will equip you with the knowledge, tools, and strategies needed to prepare, execute, and enjoy this journey safely and responsibly.

Step-by-Step Guide

1. Understand the Route and Terrain

The Four Pass Loop is a clockwise or counterclockwise circuit that begins and ends at the Maroon Bells Trailhead near Aspen, Colorado. Most hikers choose the clockwise direction, starting with the ascent of Maroon Pass, as it allows for a more gradual acclimatization to altitude. The full loop spans approximately 26 to 28 miles, depending on trail variations and detours. Elevation gains and losses are significant: each pass exceeds 12,000 feet, with Maroon Pass peaking at 12,540 feet and West Maroon Pass at 12,720 feet.

The trail is not a maintained path for its entire length. Sections are rocky, steep, and exposed, particularly on the passes where loose scree and narrow ledges require careful footing. Trail markers are sparse in high alpine zones, so navigation skills are essential. Expect a mix of forested single-track trails, alpine tundra, river crossings, and talus fields. Weather can change in minutes—sunshine can turn to hail or snow even in midsummer.

2. Choose Your Start Date and Duration

The optimal window for hiking the Four Pass Loop is mid-July through mid-September. Snow typically clears from the passes by late July, and wildflowers peak in early August. By mid-September, temperatures begin to drop significantly at night, and early snowstorms become more common. Avoid late June and early July—snowpack can still be dangerous on the passes, and river crossings may be impassable due to snowmelt.

Most hikers complete the loop in three to four days. A three-day itinerary is ambitious and requires long daily distances (9–10 miles per day) with steep elevation gains. A four-day itinerary is more sustainable and allows for rest, photography, and better acclimatization. A sample four-day split:

• Day 1: Maroon Bells Trailhead to Crater Lake (7.5 miles, 2,800 ft gain)
• Day 2: Crater Lake to West Maroon Pass to Snowmass Lake (8.5 miles, 3,200 ft gain)
• Day 3: Snowmass Lake to Frigid Air Pass to Buckskin Pass to Copper Lake (8.5 miles, 3,000 ft gain)
• Day 4: Copper Lake to Maroon Bells Trailhead (5 miles, 1,800 ft descent)

Adjust based on your fitness level and weather conditions. Always leave buffer time for delays caused by altitude sickness, weather, or trail conditions.

3. Secure a Permit

A wilderness permit is required year-round for overnight stays in the Maroon Bells-Snowmass Wilderness. Permits are issued through the USDA Forest Service and are limited to protect the fragile alpine ecosystem. Reservations open on Recreation.gov on March 1 each year, and permits for the peak season (July–September) fill within minutes.

Apply early. Choose your start date and preferred trailhead (Maroon Bells is the most popular). You can reserve up to six people per permit. If you miss the initial release, check daily for cancellations. Some permits are held for walk-up availability, but these are extremely limited—arrive at the Maroon Bells Ranger Station before 7 a.m. if attempting this route.

Permits are free, but you must carry a printed copy or digital copy on your phone. Rangers conduct random checks, and fines for non-compliance are substantial.

4. Plan Your Transportation

Private vehicles are not allowed at the Maroon Bells Trailhead during peak season (late May to mid-October). You must use the free shuttle service operated by the Aspen Skiing Company. Shuttles run from the Aspen Transit Center (115 East Hopkins Avenue) every 15–20 minutes from 6:30 a.m. to 7:00 p.m.

Plan your arrival: if you’re starting your hike at 7 a.m., aim to be at the transit center by 5:30 a.m. to secure a spot. Shuttles fill quickly, especially on weekends. Return shuttles run until 9:30 p.m., but if you’re finishing late, confirm the last departure time with the shuttle operator.

For those driving in from out of town, park at the Aspen Transit Center. There is no overnight parking at the trailhead. If you’re doing the loop in reverse, you’ll need to arrange a shuttle pickup or drop-off at the trailhead on your final day.

5. Pack Appropriately for High Altitude and Variable Weather

At elevations above 10,000 feet, the air is thinner, UV radiation is stronger, and temperatures fluctuate dramatically. Your pack should be light but fully equipped for survival in alpine conditions.

Essential Gear:

• Backpack (50–65L capacity)
• Tent (three-season, wind-resistant)
• Sleeping bag rated to 20°F (-6°C) or lower
• Sleeping pad (inflatable or foam)
• Water filter or purification tablets (Nalgene bottles or hydration bladder)
• Stove and fuel (canister stove recommended; no open fires allowed)
• Headlamp with extra batteries
• First-aid kit (include blister care, antiseptic, pain relievers, altitude sickness medication like Diamox)
• Multi-tool or knife
• Emergency whistle and space blanket

Clothing Layering System:

• Moisture-wicking base layers (synthetic or merino wool)
• Insulating mid-layer (fleece or down jacket)
• Waterproof and windproof outer shell (Gore-Tex recommended)
• Quick-dry hiking pants and shorts
• Sturdy, broken-in hiking boots with ankle support
• Warm hat, gloves, and buff
• Sunglasses with UV protection
• High-SPF sunscreen and lip balm

Weight should be kept under 25–30% of your body weight. Every ounce matters on steep ascents. Use a packing checklist and test your gear on a shorter overnight trip before attempting the full loop.

6. Navigate the Trail

Trail markers are minimal on the Four Pass Loop. A GPS device or offline map app is critical. Download the Gaia GPS or AllTrails app with offline maps of the Maroon Bells Wilderness before you leave. The trail is generally well-trodden, but in fog or snow, it can disappear entirely.

Key trail junctions to watch for:

• Maroon Lake to Crater Lake: Follow signs for the Maroon Bells-Snowmass Wilderness. The trail climbs steadily through forest before opening to alpine meadows.
• Maroon Pass Summit: Look for cairns near the top. The descent is steep and loose—use trekking poles.
• West Maroon Pass: This is the most exposed and technical section. The trail hugs a narrow ridge with significant drop-offs. Avoid crossing during high winds or after rain.
• Frigid Air Pass: Often the most scenic but least traveled. Follow cairns carefully; the trail is faint in places.
• Buckskin Pass: The final ascent before descent into Copper Lake. The trail here is rocky but well-defined.

Always carry a physical map and compass as backup. Cell service is nonexistent in the wilderness.

7. Manage Altitude Sickness

Altitude sickness is a serious risk. The trailhead starts at 9,600 feet, and you’ll reach over 12,700 feet within 24 hours. Symptoms include headache, nausea, dizziness, fatigue, and shortness of breath. In severe cases, it can progress to HAPE (High Altitude Pulmonary Edema) or HACE (High Altitude Cerebral Edema)—both life-threatening.

Prevention:

• Arrive in Aspen at least two days before your hike to begin acclimatizing.
• Hydrate aggressively: drink 3–4 liters of water daily.
• Avoid alcohol, caffeine, and heavy meals during the first 48 hours.
• Consider taking Diamox (acetazolamide) 125 mg twice daily starting 24 hours before ascent—consult your doctor.
• Ascend slowly. Don’t push for summiting passes on Day 1 if you’re not acclimated.
• Recognize symptoms early. If you or a partner shows signs of severe altitude sickness, descend immediately. Do not wait.

There are no medical facilities on the trail. Your group must be prepared to self-rescue.

8. Campsite Selection and Leave No Trace

Camp only in designated sites or in areas that have already been disturbed. There are no established campgrounds on the loop, but there are popular dispersed sites near Crater Lake, Snowmass Lake, and Copper Lake. Avoid camping within 200 feet of water sources.

Practice strict Leave No Trace principles:

• Pack out all trash—including food scraps and toilet paper.
• Use a cathole 6–8 inches deep, at least 200 feet from water, trails, and campsites.
• Use a portable stove; no fires allowed.
• Store food in bear canisters or hang it 10 feet off the ground and 4 feet from tree trunks.
• Do not pick flowers, disturb wildlife, or carve into trees.

Wildlife such as marmots, pikas, elk, and black bears are common. Never feed animals. Store food securely—bears have learned to associate campsites with food.

Best Practices

1. Travel in a Group of 3–6 People

While solo hiking is possible, the Four Pass Loop is not recommended for beginners or solo travelers. A group of three to six provides safety in case of injury, weather emergencies, or navigation errors. It also increases morale during long, strenuous days.

Assign roles: one person navigates, another manages water and food, another monitors weather and health. Rotate leadership daily to prevent fatigue.

2. Start Early, Finish Before Afternoon Storms

Thunderstorms are common in the Rockies after 1 p.m., especially in July and August. Lightning is a deadly risk on exposed ridges. Plan to summit all passes by noon. Begin your daily hikes at first light—5:30 a.m. is ideal.

Monitor the sky. If you see cumulus clouds building vertically or hear thunder, descend immediately. Do not wait. The passes are exposed rock and metal—lightning targets high points.

3. Hydrate and Eat Consistently

At altitude, your body burns calories faster and dehydration sets in quicker. Drink water every 20–30 minutes, even if you’re not thirsty. Electrolyte tablets or powder help maintain sodium and potassium balance.

Carry high-calorie, easy-to-eat snacks: trail mix, energy bars, jerky, dried fruit, peanut butter packets, and chocolate. Avoid heavy, greasy meals that can cause nausea at altitude.

4. Test Your Gear Before You Go

Never use new gear on a multi-day alpine trek. Test your tent, stove, sleeping bag, and boots on a weekend trip at a similar elevation. Make sure your water filter works with cold water. Practice setting up your tent in the dark. Burn through a canister of fuel to ensure you’ve packed enough.

Wear your boots on multiple long hikes to break them in. Blisters can end a trip quickly.

5. Respect the Environment and Local Culture

The Maroon Bells are sacred to the Ute people. This area is not just a scenic backdrop—it’s a living cultural landscape. Avoid loud music, excessive litter, or trespassing on restricted zones.

Follow all posted rules. The Forest Service enforces strict regulations to preserve the wilderness. Your actions directly impact future hikers and the ecosystem.

6. Have a Contingency Plan

Weather, injury, or fatigue can derail your plans. Know your exit points:

• From Crater Lake: hike back to Maroon Bells (7.5 miles)
• From Snowmass Lake: exit via Snowmass Creek Trail to Snowmass Village (12 miles)
• From Copper Lake: exit via Buckskin Creek Trail to Aspen (15 miles)

Carry a satellite communicator (Garmin inReach or Zoleo) to send SOS signals if you’re stranded. Inform someone off-trail of your itinerary and expected return time.

Tools and Resources

1. Essential Apps and Digital Tools

• Gaia GPS: Download the “Maroon Bells-Snowmass Wilderness” offline map. Enable topographic layers and trail overlays.
• AllTrails: Read recent trail reports from other hikers. Filter by “Four Pass Loop” and sort by date.
• Windy.com: Check high-altitude wind forecasts for West Maroon Pass and other exposed sections.
• NOAA Weather Forecast: Use the “Maroon Bells, CO” location for 7-day forecasts. Pay attention to precipitation probability and wind speed.
• Recreation.gov: Book your permit here. Set alerts for cancellations.

2. Recommended Books and Guides

• Day Hikes Around Aspen and the Maroon Bells by Steve Roper
• Colorado’s Fourteeners: From Hikes to Climbs by Gerry Roach (for context on the peaks you’ll see)
• Leave No Trace: A Guide to the New Wilderness Etiquette by The Leave No Trace Center
• Alpine Climbing: Techniques to Take You Higher by Kathleen K. M. Haltom (for navigating exposed terrain)

3. Gear Recommendations

• Backpack: Osprey Atmos AG 65 or Deuter Aircontact Lite 65+10
• Tent: MSR Hubba Hubba NX 2 or Big Agnes Copper Spur HV UL2
• Sleeping Bag: Marmot Limelight 20 or NEMO Hornet 20
• Stove: MSR PocketRocket 2 or Jetboil Flash
• Water Filter: Sawyer Squeeze or Katadyn BeFree
• Footwear: La Sportiva Nucleo High GTX or Salomon Quest 4D 3 GTX
• Trekking Poles: Black Diamond Alpine Carbon Cork or Leki Micro Vario Carbon
• Satellite Communicator: Garmin inReach Mini 2

4. Local Resources and Contact Points

• Aspen Chamber Resort Association: Provides shuttle schedules and local trail updates.
• USDA Forest Service – Maroon Bells Ranger Station: Located at 11000 Maroon Creek Road, Aspen. Open 8 a.m.–4 p.m. daily during peak season. Staff can provide real-time trail conditions and weather advisories.
• Aspen Outfitters: Offers gear rentals, shuttle bookings, and guided group trips.

Real Examples

Example 1: The Experienced Backpacker – Sarah and Mark

Sarah and Mark, both 38 and seasoned hikers from Colorado, completed the Four Pass Loop in three days in early August. They started at 6 a.m. on Day 1, reached Crater Lake by 3 p.m., and camped with a view of the Maroon Bells. They took Diamox the night before and drank 4 liters of water daily. On Day 2, they summited West Maroon Pass by 11 a.m. to avoid afternoon thunderstorms. They carried extra layers and a bivy sack in case of delays. On Day 3, they descended through Buckskin Pass and finished at the trailhead by 5 p.m. They reported the trail was in excellent condition, with wildflowers blooming and no snow on the passes. Their biggest challenge? Sleep deprivation due to cold nights. They now recommend a down quilt for added warmth.

Example 2: The First-Time Multi-Day Hiker – The Chen Family

The Chens, a family of four from Texas, attempted the loop in four days with their 14-year-old daughter. They arrived in Aspen three days early to acclimate. They hired a guide for Day 1 to learn navigation and safety protocols. They used a bear canister and pre-packaged meals. Their daughter developed mild altitude sickness on Day 2 but recovered after descending 1,000 feet to Snowmass Lake. They ended the trip early but completed 80% of the loop. They said the experience was life-changing and plan to return next year with a longer itinerary.

Example 3: The Solo Hiker – James, 52

James, a retired engineer from Oregon, hiked the loop alone in September. He carried a Garmin inReach and sent daily check-in messages. He started early each day and camped near water sources. He encountered a moose on Day 3 and gave it a wide berth. He described the silence as “profound.” He lost his glove on West Maroon Pass but used a spare. He finished the loop in 3.5 days and called it “the most rewarding physical challenge of my life.” He emphasized the importance of mental resilience: “You’re alone with your thoughts, your body, and the mountains. That’s the real test.”

FAQs

Is the Four Pass Loop suitable for beginners?

No. The Four Pass Loop is not recommended for beginners. It requires prior backpacking experience, high-altitude familiarity, strong navigation skills, and physical conditioning. Beginners should start with shorter, lower-elevation loops like the Maroon Lake Scenic Trail or the Crater Lake Trail before attempting this route.

Do I need to carry bear spray?

Bear spray is not required by law, but it is highly recommended. Black bears are present in the area, and while they are typically shy, they may be attracted to food smells. Store food properly and carry bear spray in an accessible holster. Know how to use it before you go.

Can I do the Four Pass Loop in one day?

Technically, yes—but it is extremely dangerous and not advised. The loop is 26–28 miles with over 7,000 feet of elevation gain. Even elite athletes take 14–16 hours. You risk altitude sickness, exhaustion, and being caught in a storm. Do not attempt a one-day hike.

Are dogs allowed on the Four Pass Loop?

Yes, dogs are allowed but must be under control at all times. They are not permitted on some designated wilderness trails during certain seasons. Carry extra water for your dog and clean up waste. Many hikers choose to leave pets at home due to the difficulty and exposure.

What’s the best time of year to hike the Four Pass Loop?

Mid-July to mid-September is ideal. July brings wildflowers, August offers stable weather, and September has fewer crowds and crisp air. Avoid June and October due to snow and early winter storms.

What should I do if I get lost on the trail?

Stop immediately. Do not panic. Use your GPS or map to reorient yourself. If you cannot determine your location, stay put. Activate your satellite communicator. Signal for help using a whistle or mirror. Do not descend blindly—many trails are not visible from above.

Is there cell service on the trail?

No. There is no reliable cell service anywhere on the Four Pass Loop. Do not rely on your phone for navigation or emergency communication. Use a satellite device.

How cold does it get at night?

Nighttime temperatures range from 30°F to 50°F (-1°C to 10°C), even in summer. At higher elevations, especially on passes, temperatures can drop below freezing. Always pack a warm sleeping bag and extra layers.

Can I camp anywhere along the trail?

No. You must camp at least 200 feet from water sources and trails. Avoid pristine areas. Use established sites when possible. Dispersed camping is allowed, but only where the ground is already impacted. Follow Leave No Trace guidelines strictly.

How do I refill my water?

There are multiple reliable water sources: Maroon Creek, Crater Lake outlet, Snowmass Creek, and Copper Lake. Filter or treat all water. Even clear alpine water can contain giardia. Carry at least 3 liters capacity and refill at every opportunity.

Conclusion

The Four Pass Loop in the Maroon Bells is more than a hike—it’s a transformative journey through some of the most breathtaking alpine terrain on Earth. It challenges your body, sharpens your mind, and deepens your connection to nature. The steep ascents, the howling winds on exposed ridges, the stillness of a mountain lake at dawn—these are moments that stay with you long after your boots are cleaned and packed away.

Success on this loop comes not from speed or strength alone, but from preparation, humility, and respect—for the land, for the weather, and for your own limits. Every hiker who completes this route carries a quiet pride, knowing they’ve walked through a landscape few will ever see, and even fewer will ever understand.

Use this guide not just as a checklist, but as a compass. Let it inform your decisions, deepen your awareness, and protect your safety. The mountains don’t care how many photos you post or how fast you finish. They reward patience, mindfulness, and reverence.

Plan wisely. Pack thoughtfully. Start early. Respect the wilderness. And when you stand on the summit of West Maroon Pass, looking down at the Maroon Bells glowing in the afternoon light, you’ll know—this is why we hike.