Ptarmigan Lake, Bear Lake Trailhead, Rocky Mountain National Park, Colorado

Ptarmigan Lake - 11.8 miles

Bear Lake Trailhead

View of Ptarmigan Lake on the descent from the Tonahutu Trail

View of Ptarmigan Lake on the descent from the Tonahutu Trail

Round-Trip Length: 11.8 miles (distance and elevation gains will vary by route)
Start-End Elevation: 9,475' - 11,493' (12,347' max elevation)
Elevation Change: +2,018' net elevation gain (+3,763' total roundtrip elevation gain)
Skill Level: Moderate-Strenuous
Dogs Allowed: No
Bikes Allowed: No
Horses Allowed: Yes
Related Trails:

Ptarmigan Lake - 11.8 Miles Round-Trip

Ptarmigan Lake (11,493') is located just west of the Continental Divide in a large bowl over treeline. No trail reaches the lake, however a short cross-country route splits off the Tonahutu Trail down open tundra into the basin.

Trail Map | Photo Gallery

The shortest route to Ptarmigan Lake begins at Bear Lake and runs 4.3 miles to Flattop Mountain, where you'll turn north on the Tonahutu Trail to Ptarmigan Pass. Once in this vicinity you can identify the approximate location and descend to the lake.

Ptarmigan Lake is ~1.5 miles from Flattop, and exact distances will vary by route through the tundra.

The lake may initially be concealed on the approach, but its location is fairly easy to determine by key landmarks such as Snowdrift Peak and Ptarmigan Point. Terrain is generally mild between Flattop and Ptarmigan, save the final steep drop into the bowl. 

Ptarmigan Lake is ringed by a narrow band of thick alpine grass suitable for camping. It's the largest of three alpine lakes that drain through Bench Lake into the North Inlet on the west side of Rocky Mountain National Park.

Most of this trail runs above treeline at high elevations. Get an early start and watch weather closely. Allow ample time for the climb back to Flattop, and to get back under treeline. Start early to avoid afternoon storms.

The tundra is extremely fragile; stay on maintained trails as long as possible, tread lightly and walk on rocks whenever possible to minimize impact:

The trail rises over Bear Lake to the Odessa Lake - Mill Creek Basin Trail split (.45 miles : 9,725'). It climbs steadily in a spruce-fir forest to the Flattop Mountain Trail (1.0 mile : 9,965'), which steepens on a rough, winding path to Dream Lake Overlook (1.6 miles : 10,470').

It climbs steadily to Emerald Lake Overlook (2.9 miles : 11,357') and gradually moderates through treeline with exceptional views of the Mummy Range and Longs Peak (2.5 - 3.0 miles : 11,440'). Travel steadies up to a hitchrack (3.9 miles, 12,135') with a great look at Hallet Peak across the Tyndall Glacier gorge.

The trail scales a perennial snowfield over the hitchrack and levels to Flattop Mountain (4.3 miles : 12,324'). No sign marks the summit, however the Flattop Mountain Trail - Tonahutu Trail junction is generally recognized as the summit.

Turn right (north) across broad, level tundra to the North Inlet - Tonahutu Trail split (4.6 miles : 12,312'). Keep right on the Tonahutu Trail, which rises nominally to Ptarmigan Pass with exceptional views east down to Lake Helene and Two Rivers Lake.

From this point you can drop toward the lake, or continue a bit further north on the trail. Continuing is preferable, as you'll have access to amazing views down Tourmaline Gorge to Odessa Lake, and a milder descent toward Ptarmigan.

Snowdrift Peak (12,274') stands prominently to the west, a useful landmark that will draw you to a steep lip right over the lake (5.7 miles). From here you can wind down steeper slopes to the east side of Ptarmigan Lake (5.9 miles : 11,493').

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N40 18.714 W105 38.760 — 0.0 miles : Bear Lake Trailhead
  • N40 19.048 W105 38.636 — .45 miles : Bierstadt Lake access trail split
  • N40 18.986 W105 39.187 — 1.0 miles : Flattop Mountain - Odessa Lake trail split
  • N40 18.753 W105 39.550 — 1.6 miles : Dream Lake overlook
  • N40 18.851 W105 39.776 — 1.95 miles : Rocky climb in thinning forest
  • N40 18.876 W105 39.896 — 2.25 miles : Begin transition through treeline
  • N40 18.872 W105 40.223 — 2.85 miles : Emerald Lake Overlook
  • N40 18.963 W105 40.351 — 3.05 miles : Steady travel in rocky tundra
  • N40 18.775 W105 40.779 — 3.5 miles : Grade moderates with views of Notchtop
  • N40 18.617 W105 41.059 — 3.9 miles : Hitchrack at base of perennial snow field
  • N40 18.535 W105 41.415 — 4.3 miles : Flattop Mountain - Tonahutu Trail split
  • N40 18.574 W105 41.683 — 4.6 miles : North Inlet - Tonahutu Trail split
  • N40 18.543 W105 42.207 — 5.2 miles : Open tundra travel
  • N40 18.581 W105 42.422 — 5.65 miles : Open tundra travel
  • N40 18.682 W105 42.647 — 5.7 miles : Lip over lake

Worth Noting

  • Tread carefully and delicately across the tundra. Stay on designated trails and walk on rocks whenever possible to minimize impact

Camping and Backpacking Information

Permits are required for all overnight stays. Fires are not permitted within Rocky Mountain National Park. There are no designated backcountry campsites on the Flattop Mountain Trail or at Ptarmigan Lake. Zone Camping only.

There are several campsites accessible from the Bear Lake Trailhead (east side of Divide), and along the Tonahutu Trail (west side of Divide):

Camp safely away from dead trees, as close as possible to the silver metal arrowhead posted at each site. Red arrowheads on trees provide additional guidance to each campsite from the main trail:

Bear Lake Area Campsites:

Sourdough Backcountry Campsite (10,628')

  • There is one designated site located 2.65 miles from the Bear Lake Trailhead, 60 yards north of the main trail on the south flank of Joe Mills Mountain. The site is located in a level spruce bench. One bear box is available. Water is available year-round from the North Fork of Mill Creek, Lake Helene and Two Rivers Lake.

Odessa Lake Backcountry Campsite (10,065')

  • There are two designated sites located 4.1 miles from the Bear Lake Trailhead in a spruce-fir stand east of Odessa Lake on the north side of its outlet stream. The sites are located just over the log bridge crossing of this stream. One bear box is available. Water is available year-round from Odessa Lake and its outlet stream.

Fern Lake Backcountry Campsite (9,530')

  • There is one group site and four individual sites located 5.1 miles and 5.3 miles from the Bear Lake Trailhead, respectively. Both are located in a mixed pine forest on the NE and NW sides of Fern Lake, respectively. Each has access to a bear box and privy. Water is available year-round from Fern Lake, its inlet and outlet streams.

Tonahutu Trail Campsites:

Haynach Backcountry Campsites (includes Llama Site) (10,678')

  • The Haynach Backcountry Campsites are located 7.2 miles from the Green Mountain Trailhead on the Haynach Lakes Trail. The sites are located in a spruce-fir glade on the edge of a meadow, just east of Haynach Creek. The sites are .5 miles north of the Tonahutu Trail split. 2 sites are available (permit required for llama stock).

Tonahutu Group and Stock Backcountry Campsite (10,160')

  • The Tonahutu Group and Stock Backcountry Campsite is located 6.6 miles from the Green Mountain Trailhead. The site is located in a heavy spruce-fir forest on the banks of Tonahutu Creek. 1 site and a privy is available.

Tonahutu Meadows Backcountry Campsites (10,050')

  • The Tonahutu Meadows Backcountry Campsites are located 6.1 miles from the Green Mountain Trailhead. The sites are located in a spruce-fir stand between Tonahutu Meadows and Tonahutu Creek on the south side of the trail. 2 sites are available.

Fishing Information

A valid Colorado fishing license is required for all persons 16 years of age or older to fish in Rocky Mountain National Park. No other permit is necessary; however, special regulations exist. It's your responsibility to know and obey them. 

Due to the dynamic nature of fisheries management, fishing regulations can change at anytime. Special closures may be put in place above and beyond what is listed here. Contact the park before heading out for current information.

  • Certain waters in the park with restored native fish populations are open year round during daylight hours, except as indicated. Use barbless hooks only. Any and all fish species taken must be immediately returned to the water unharmed. No bait is permitted by any age angler in catch-and-release areas.
  • Method of Capture: Each person shall use only one hand-held rod or line. A 'second rod stamp' is not honored in park waters. Only artificial lures or flies with one (single, double, or treble) hook with a common shank may be used. "Artificial flies or lures" means devices made entirely of, or a combination of, materials such as wood, plastic, glass, hair, metal, feathers, or fiber, designed to attract fish. This does not include: (a) any hand malleable material designed to attract fish by the sense of taste or smell; (b) any device to which scents or smell attractants have been externally applied; (c) molded plastic devices less than one and one-half inch in length; (d) foods; (e) traditional organic baits such as worms, grubs, crickets, leeches, minnows, and fish eggs; and (f) manufactured baits such as imitation fish eggs, dough baits, or stink baits. Fly fishers may utilize a two hook system, where one hook is used as an attractant.
  • While in possession of any fishing equipment, bait for fishing (insects, fish eggs, minnows, or other organic matter) or worms is prohibited. Children 12 years of age or under, however, may use worms or preserved fish eggs in all park waters open to fishing except those designated as catch-and release areas.
  • No bait or worms are allowed in catch-and-release waters.
  • Use of lead sinkers (or other lead fishing materials) is strongly discouraged.

Rules and Regulations

  • A $20 Day Use Fee is required to enter Rocky Mountain National Park (or $30 for a 7 Day Pass).
  • Dogs are not permitted on hiking trails in Rocky Mountain National Park.

Directions to Trailhead

Bear Lake Trailhead is located 8.9 miles from the Beaver Meadows Entrance Station in Rocky Mountain National Park.

Just past the Beaver Meadows entrance station, turn left onto Bear Lake Road. The Bear Lake Trailhead is located at the end of this road. Additional parking and alternative access can be found at the Glacier Gorge Trailhead. This will add an additional 1 mile roundtrip to the hike.

Contact Information

Rocky Mountain National Park
Visitor Information:

Backcountry Office:

Campground Reservations:

Emergency Dispatch:

Trip Reports

There are no trip reports on this trail.


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