Summer view of the Maroon Bells above Maroon Lake and a green valley with wildflowers, near Aspen, Colorado

Four Pass Loop Itinerary: 4 Days, Permits and Shuttle

About 26 miles (42 km) over four passes above 12,000 feet (3,658 m), and a permit for every night plus a way into Maroon Lake.

26.5 mi · 4 days · Hard
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Photo: Rhododendrites, CC BY-SA 4.0

The Four Pass Loop is the standard backpack in the Maroon Bells-Snowmass Wilderness outside Aspen: about 26 miles (42 km) from Maroon Lake over West Maroon Pass, Frigid Air Pass, Trail Rider Pass and Buckskin Pass, every one above 12,000 feet (3,658 m), past Crater Lake and Snowmass Lake. This page walks it clockwise on the map from Maroon Lake in four days. Visit Maroon Bells calls the route difficult because of the elevation and the terrain, and it is a trip for people who already carry a pack over high passes.

The decision that matters is the permit, not the miles. Every night in a permit zone needs a reservation on Recreation.gov, the zones hold only 6 to 17 groups a night, and the reservation for each zone is the zone you must sleep in. Pick the zones and the dates first, then the trailhead parking or shuttle. The four days below are one workable split; the official pages give no per-day distances, so every leg distance here was measured along the OpenStreetMap trail line, which comes to 26.5 miles (42.7 km) in total against the 26 miles (42 km) Visit Maroon Bells quotes.

The loop shares its first and last 1.7 miles (2.8 km) with the trail to Crater Lake, and you finish where you started. The pages do not say whether one shuttle ticket or parking reservation covers a multi-night trip, so ask before you book. You must camp in the zone you booked for each night, so there is no slack for a rest day unless you book it. Read the season section before you book.

The Route on the Map

Each day in its own color, with the start and every night's stop numbered along the way.

Loading map...

Elevation Profile

Highest 12,550 ft (3,825 m) · lowest 9,580 ft (2,920 m)

12,550 ft9,580 ft123
0 mi26.5 mi (42.7 km)

Route line: OpenStreetMap contributors (ODbL), simplified. Elevations: USGS 3D Elevation Program (public domain).

Day by Day

4 legs and 3 nights on the way, each in a different place.

  1. Day 1

    Day 1: Maroon Lake up the West Maroon valley

    Maroon Lake TrailheadtoWest Maroon valley campsites

    Distance
    4.9 mi 7.9 km
    Up
    1,790 ft 546 m
    Down
    120 ft 38 m

    Climb computed from USGS 3D Elevation Program (public domain), not an official figure.

    A gentle first day that keeps the legs fresh for the two passes tomorrow: 4.9 miles (7.9 km) along Maroon Lake, up past Crater Lake and into the West Maroon valley, with the pass still 1.5 miles (2.4 km) ahead. The trail meets the Maroon-Snowmass Trail at Crater Lake, where the loop will return on day 4.

    If you want a shorter first day or a designated site, Crater Lake has numbered campsites that are reserved on the same permit (no fires there); the day then becomes 1.7 miles (2.8 km) and day 2 gets longer. Whichever you choose, the zone you book is the zone you sleep in, and the camps in this valley are in a zone you confirm on the Forest Service zone map.

    Sleep
    West Maroon valley (check the permit zone map for the zone) · Backcountry campsite · How to book
    Water
    West Maroon Creek runs beside the trail and Crater Lake is 1.7 miles (2.8 km) in; both are mapped.Reported Nov 2026, verify before you go
  2. Red-brown ridge of Sievers Mountain rising above a green alpine meadow and scree slopes, seen from the West Maroon Pass area
    Day 2

    Day 2: West Maroon Pass and Frigid Air Pass

    West Maroon valley campsitestoUpper North Fork of the Crystal River

    Distance
    7.1 mi 11.4 km
    Up
    1,950 ft 594 m
    Down
    2,700 ft 823 m

    Climb computed from USGS 3D Elevation Program (public domain), not an official figure.

    The first big day, 7.1 miles (11.4 km) with two of the four passes. West Maroon Pass comes about 1.5 miles (2.4 km) from the camp; beyond it the loop turns off the West Maroon Trail onto the North Fork Crystal River Trail and climbs to Frigid Air Pass, then drops into Fravert Basin and the North Fork.

    Start early. Both passes are above timberline, and Visit Maroon Bells says lightning occurs in the afternoon, so plan to be off high terrain then. The camps here are mapped in OpenStreetMap along the North Fork; the Forest Service permit decides which zone you may use.

    Sleep
    Upper North Fork of the Crystal River (check the permit zone map for the zone) · Backcountry campsite · How to book
    Water
    Streams and lakes are mapped on both sides of each pass; the North Fork of the Crystal River runs beside the camps.Reported Nov 2026, verify before you go

    Photo: Tom Pratt, CC BY 2.0

  3. Day 3

    Day 3: Trail Rider Pass to Snowmass Lake

    Upper North Fork of the Crystal RivertoSnowmass Lake

    Distance
    6.0 mi 9.6 km
    Up
    2,230 ft 679 m
    Down
    1,540 ft 470 m

    Climb computed from USGS 3D Elevation Program (public domain), not an official figure.

    Six miles (9.6 km) with one pass. The loop follows the North Fork down to the North Fork Cutoff Trail, which leads to the Geneva Lake Trail, then climbs to Trail Rider Pass and descends to Snowmass Lake. Snowmass Lake has its own permit zone with 13 groups a night, and campfires are prohibited above 10,800 feet (3,292 m), which includes the lake. The day is short enough to leave time to settle in before an afternoon storm.

    Sleep
    Snowmass Lake zone · Backcountry campsite · How to book
    Water
    Streams in the North Fork valley are mapped, and Snowmass Lake is the camp.Reported Nov 2026, verify before you go
  4. The Maroon Bells seen through spruce trees from the Crater Lake area, with snow patches on the peaks under a summer sky
    Day 4

    Day 4: Buckskin Pass and back to Maroon Lake

    Snowmass LaketoMaroon Lake Trailhead

    Distance
    8.6 mi 13.8 km
    Up
    1,790 ft 547 m
    Down
    3,340 ft 1,018 m

    Climb computed from USGS 3D Elevation Program (public domain), not an official figure.

    The last and longest day, 8.6 miles (13.8 km): about 3.8 miles (6.1 km) of climbing from Snowmass Lake to Buckskin Pass, then a long descent to the Crater Lake junction and the last 1.7 miles (2.8 km) to Maroon Lake.

    The last return shuttle from the Maroon Lake Trailhead leaves at 5 p.m. (RFTA), so time the descent if you used the shuttle in. If you drove with a parking reservation, check its rules too.

    Water
    Streams along the Maroon-Snowmass Trail are mapped; Crater Lake and Maroon Lake are on the last stretch.Reported Nov 2026, verify before you go

    Photo: Whyleesaa, CC BY-SA 4.0

Permits

A permit is required

Overnight permits are required in this part of the Maroon Bells-Snowmass Wilderness all year and must be reserved in advance on Recreation.gov. You reserve a permit zone for every night you camp, and nights in Crater Lake must be in a numbered designated site. A permit costs $10 per person per night from May 1 to October 31 (no night fee outside those dates), plus a non-refundable $6 reservation fee per permit; children 16 and under are free. Most permits cover up to 4 people, some zones sell large-group permits for 5 to 10, and a permit runs up to 7 nights. Each person can hold two permits per calendar year. Zone quotas are small: 15 groups a night in the Maroon zone, 7 in East Fork, 17 in North Fork, 8 at Geneva Lake, 13 at Snowmass Lake, 6 in Upper Snowmass, and 11 designated sites at Crater Lake. The Forest Service publishes a permit zone map and the designated-site maps; read them before you pick nights, because the zone you book is the zone you must sleep in. The permit holder or the alternate leader must be on the trip, and the alternate cannot be added after you buy, so enter one before checkout. A permit cannot be booked into a release window that has not opened, so a trip that runs from July 31 into August has to wait for the August release. The printed permit and photo ID must be carried. You can print a permit 14 days before the trip, but after printing it cannot be changed or refunded. Cancel at least 48 hours before the start for a refund of the fee, minus the $6.

The lottery

There is no lottery. Permits release in windows at 8 a.m. Mountain Time on Recreation.gov: April through July trips open on February 15 and August through November trips on June 15, and Recreation.gov's 2026 listing opened December through March trips on October 15. Visit Maroon Bells suggests logging in at 7:55 a.m. with your zones in the cart, because the popular nights go quickly. In 2026 those dates were February 15, June 15 and October 15; check the permit page for the current ones.

The official permit page

Getting There and Back

How to reach the start of the Four Pass Loop Itinerary, and how to get home from the end.

The start

The loop starts and ends at the Maroon Lake Trailhead in the Maroon Bells Scenic Area outside Aspen. Anyone starting there needs a parking or shuttle bus reservation in the season; the permit confirmation email carries a link to reserve one, and Visit Maroon Bells does the booking. The shuttle leaves the Maroon Bells Welcome Center at Aspen Highlands (75 Boomerang Road, Aspen) and takes about 15 minutes. In 2026 it ran from May 22 to October 18 at $16 for adults and $10 for children 12 and under and adults 65 and over, with RFTA buses connecting from Aspen, Snowmass Village and the valley towns; see RFTA.

The end

You finish where you started, on Maroon Lake, so there is no shuttle between ends. RFTA says the last return shuttle from the Maroon Lake Trailhead is at 5 p.m., which matters if you come off Buckskin Pass late on the last day: ask Visit Maroon Bells what applies to your ticket or parking reservation, since the pages do not spell out multi-night stays.

Parking

Trailhead parking at Maroon Lake is limited and needs a reservation: $10 per vehicle in 2026. Between May 22 and October 18 the vehicle must arrive before 8 a.m. or after 5 p.m., depending on the reservation type, so people who drive come early and the shuttle starts at 7 a.m. You choose trailhead parking or a shuttle ticket, not both. After the shuttle ends for the year (October 19 in 2026), a parking reservation is the only way in. Camping in the parking lot is not allowed. There is no water at the Maroon Lake Trailhead; fill up at the Welcome Center before boarding. Ask Visit Maroon Bells how long a parking reservation holds a car for a multi-night trip, which the pages do not say.

Safety

  • Snow and water decide the early season. Visit Maroon Bells says early summer snowmelt makes the river crossings perilous and deep snow persists on the passes until late in the summer. All four passes are above 12,000 feet (3,658 m), so when you can see a snowfield on the climb, plan for slower days or a later date, and look at the current conditions before you pay for a permit you cannot change after printing.

  • Thunderstorms in the mountains build in the early afternoon. The National Weather Service says thunderstorms typically develop in the afternoon, so hike early, and that if you hear thunder above timberline you should go quickly to a lower area below it and get off ridges and peaks. On this loop every pass is above timberline, so cross each one in the morning. Stay in safe shelter at least 30 minutes after the last thunder; in the backcountry that means getting well below the passes and waiting.

  • This is bear country, and the rule is firm. Food, trash and anything scented must be stored in an IGBC-approved bear-resistant container, and the permit page says visitors without one will be ticketed and required to leave. Visit Maroon Bells adds that anything with a scent should be stored at least 100 feet (30 m) from camp.

  • Plan your own water and your own exit. Visit Maroon Bells advises carrying extra water, and the loop has long stretches above treeline. There are no toilets in the wilderness: use a WAG bag or dig a hole 6 to 8 inches (15 to 20 cm) deep at least 200 feet (61 m) from water, camp and trails, and pack out the toilet paper.

  • Campfires are prohibited at the designated sites at Crater Lake and above 10,800 feet (3,292 m), which includes Snowmass Lake. Dogs must be on a leash. Bicycles and other mechanized equipment, including drones, are banned in designated wilderness. Camp in an already established site about 70 big steps from trails and water in the zones that allow dispersed camping.

Four Pass Loop Itinerary: FAQ

Do you need a permit for the Four Pass Loop?

Yes, for overnights. The Forest Service requires an overnight permit for the busiest parts of the Maroon Bells-Snowmass Wilderness, including the Four Pass Loop, booked on Recreation.gov for each permit zone and night. It costs $10 per person per night from May 1 to October 31, plus a $6 reservation fee per permit.

When do Four Pass Loop permits go on sale?

At 8 a.m. Mountain Time on Recreation.gov: February 15 for April through July trips and June 15 for August through November trips, with December through March trips opening on October 15. There is no lottery.

Do you need a bear canister on the Four Pass Loop?

Yes. Food, trash and anything scented must be kept in an IGBC-approved bear-resistant container, and the permit page says visitors without one will be ticketed and required to leave.

Do you need a parking or shuttle reservation at Maroon Lake?

Yes, in the season. The permit confirmation email links to the reservation for Maroon Bells parking or the RFTA shuttle. In 2026 the shuttle ran from May 22 to October 18 and trailhead parking ran to October 31.

How many days does the Four Pass Loop take?

This page splits it into four days of 4.9, 7.1, 6.0 and 8.6 miles (7.9, 11.4, 9.6 and 13.8 km). The distances are measured on the OpenStreetMap trail line; the pace is yours, and snow or storms can add a day.

When is the best time for the Four Pass Loop?

July through September. From early October to late June the passes and campsites are snow covered, and Visit Maroon Bells says deep snow persists on the passes until late in the summer.

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