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

Flattop Mountain - 8.6 miles

Bear Lake Trailhead

Looking north across the top of Tyndall Glacier and Flattop Mountain

Looking north across the top of Tyndall Glacier and Flattop Mountain

Round-Trip Length: 8.6 miles
Start-End Elevation: 9,475' - 12,324' (12,332' max elevation)
Elevation Change: +2,849' net elevation gain (+2,909' total roundtrip elevation gain)
Skill Level: Strenuous
Dogs Allowed: No
Bikes Allowed: No
Horses Allowed: Yes
Related Trails:

Flattop Mountain - 8.6 Miles Round-Trip

Flattop Mountain (12,324') is located 4.3 miles from Bear Lake Trailhead in Rocky Mountain National Park. The summit is best described as a long, flat saddle on the Continental Divide between Hallet Peak and Ptarmigan Point. This level expanse offers a rare opportunity to explore the tundra with relative ease. The Flattop Mountain Trail closely follows a route used by native tribes to reach alpine hunting grounds.

Trail Map | Photo Gallery

A strenuous climb on well-kept trails leads through diverse forests and open tundra to the summit, with exceptional views and wildlife viewing throughought. 

50% of this trail runs above treeline. Expect strong sun, wind, cool temperatures and rapidly changing weather. Get an early start to avoid afternoon storms:

The trail rises quickly over Bear Lake through young aspen 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 considerably on a rough, winding path.

Thick timber breaks at Dream Lake Overlook with good views up Glacier Gorge, and of Keyboard of the Winds on Longs Peak's west ridge (1.6 miles : 10,470').

Steady, steep climbing resumes in a thinning forest to Emerald Lake Overlook (2.9 miles : 11,357') with a revealing look over the valley carved by Tyndall Glacier, one of five active glaciers in the Park.

Grades moderate as you transition through treeline (2.5 - 3.0 miles : 11,440'), where the forest is gradually reduced to thin bands of willow and krummholz.

Krummholz - a German word meaning twisted wood - describes the stunted, irregular growth patterns of trees in the ecological transition zone between subalpine forests and alpine tundra. Poor soil, thin air, strong winds, and extreme weather limit growth at these elevations.

Still, the tundra's grasses, lichens, and wildflowers support marmot, pika, ptarmigan, elk, bighorn sheep and mountain goat.

Grades steady on a well-defined path into open tundra. Tread carefully over snowfields, and use cairns for guidance. The trail reaches a hitchrack (3.9 miles, 12,135') with a close look at Hallett Peak (12,713') across the Tyndall Glacier gorge.

The trail scales a perennial snowfield over the hitchrack and levels on the final run up 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 your final destination.

A good map will help you identify landmarks such as Hallett Peak, Otis Peak (12,486'), Taylor Peak (13,153'), Longs Peak (14,259'), Notchtop Mountain (12,129'), Ptarmigan Point (12,363') and portions of the Mummy Range, Never Summer Range and Grand Lake area.

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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 Summit

Worth Noting

  • Tyndall Glacier spans the saddle between Flattop Mountain and Hallett Peak, and the U-shaped valley below it. Tyndall Glacier is one of five active glaciers in the Park.
  • Hallet Peak is an additional .7 miles and +389' climb from Flattop Mountain. Follow an unnamed but cairn-marked path south from the Flattop - Tonahutu Trail junction to the summit.
  • 50% of this trail runs above treeline and is highly exposed. Anticipate strong sun, wind, cool temperatures, and rapidly changing weather conditions. Get an early start to avoid afternoon thunderstorms.
  • This is a heavily used trailhead with limited parking. Arrive early to secure a space and avoid crowds.

Camping and Backpacking Information

There are no designated backcountry campsites on the Flattop Mountain Trail, however there are several nearby sites accessible from the Bear Lake Trailhead.

Permits are required for all overnight stays. Fires are not permitted within Rocky Mountain National Park. 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:

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.

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

Flattop Mountain is accessed from the Bear Lake Trailhead in Rocky Mountain National Park. It's located 8.9 miles from the Beaver Meadows Entrance Station on Bear Lake Road.

Turn left onto Bear Lake Road just past the Beaver Meadows entrance station. 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.


"Snow drifts became fairly continuous between the Dream Lake Overlook (1.6 miles) and Emerald Lake Overlook (2.9 miles). The trail can be hard to find in a few places but it was pretty easy to follow tracks and ribbons on trees. Once above treeline the trail was mostly clear, except for a few long snowfields in the usual places. These were much easier to navigate and regain the trail. Poles were extremely helpful (especially across snow drifts in the trees), and traction was a plus but not essential. The snow appears to be melting fast, and I wouldn't be surprised if snow is a non-factor in a week or so. I didn't go up Hallet but got a very good look, and it seems like a pretty clear and straight forward walk-up right now. As with most hikes I've done and heard about recently in RMNP and the Indian Peaks, the snow is deepest in the trees starting in the low to mid 10,000s, and things clear (or at least get easier to pass and navigate) once above treeline."
Brandon Consedine  -  Boulder  -  Date Posted: June 27, 2017
"Incredible Hike! Pretty strong wind gusts once above the treeline - pack gear for all weather. Trekking poles advised for descent. Take your time and enjoy the gorgeous views along the trail. Pikas, Marmots and lots of birds in the rocks."
Kory Wynegar  -  Texas  -  Date Posted: August 26, 2013
"Really enjoyed the hike. Not much snow yet this year. Only used my traction devices in a few spots. The trail is steady ascend which is why the difficulty is ranked high. No dangerous drop offs however. Like any high country hiking, watch the weather."
Shannon Dizmang  -  United States  -  Date Posted: December 3, 2012


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