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Rocky Mountain National Park

Rocky Mountain National Park: Tonahutu Loop

Cross elk-filled woods and bighorn-busy flats on this park's quiet side.

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If locals say “Go high or go home” is this park’s unofficial motto, then the 25.2-mile tundra-topped Tonahutu Loop is its poster child. Park at the Tonahutu/North Inlet trailhead on RMNP’s less-trafficked west side, and go north on the Tonahutu Trail. Hike along lodgepole pine-lined trail to the junction with the Tonahutu Spur Trail at .8 mile.

Ramble beside Tonahutu Creek to where the forest thins at mile 3.2. Big Meadows, a two-mile-long field flanked by spruce and filled with a dozen varieties of wildflowers (bloom starts in July) stays hidden until after the junction with the Green Mountain Trail. In 1.7 miles, pass Sunset campsite, and, permit willing, continue 3.6 miles past seven more campsites and 30-foot Granite Falls, to Hynach llama camp, via a .4-mile hike on the Hynach Lakes Trail. Located at 10,707 feet in a pine-bottomed valley, this campsite offers a surround-sound wilderness experience—a rushing stream, yipping coyotes, and bugling elk.

Return to the Tonahutu Trail junction early the next morning (by 7 a.m.) to avoid summer’s afternoon thunderstorms on the exposed alpine miles ahead, and ascend across granite talus to Bighorn Flats. Mountain views open to the west on this treeless slope. Climb toward Ptarmigan Point (12,363 feet) on the Continental Divide. At the Flattop Mountain Trail junction, drop your pack and hike to the rock-lined rim at Flattop’s 12,324-foot summit above Emerald Lake. The trail continues south past knee-high cairns with eastern views of 14,259-foot Longs Peak.

At mile 15.7, descend 1,400 feet in 1.3 miles on switchbacks to Hallett Creek. Continue down with occasional views of 12,324-foot Ptarmigan Mountain. After North Inlet Junction campsite, there’s a second string of camps. Aim for the dispersed zone south of 60-foot Cascade Falls. The next day, knock off the final three miles between high and home.

INFO For information on permits, current trail and camp conditions, and wilderness guidelines, go to nps.gov/romo/planyourvisit/backcountry.htm

PERMIT A wilderness permit is required for all overnight camping in the backcountry. Reservations accepted ($20 administrative fee for permits during peak season). nps.gov/romo/planyourvisit/backcntry_guide.htm

CONTACT Rocky Mountain National Park, (970) 586-1206; nps.gov/romo

GEAR UP: Rent bear canisters (required, $5/day) at Never Summer Mountain Products. 919 Grand Lake Ave., Grand Lake. (970) 627-3642.

-Mapped by Casey Lyons

Trail Facts

  • Distance: 40.6

Waypoints

TON001

Location: 40.256525, -105.814723

Park at the Tonahutu/North Inlet trailhead on RMNP’s less-trafficked west side, and go west, then north on the Tonahutu Trail. Hike along lodgepole pine-lined trail to the junction with the Tonahutu Spur Trail at .8 mile.

TON002

Location: 40.265398, -105.822521

Turn right, heading north.

TON003

Location: 40.297075, -105.813575

Ramble beside Tonahutu Creek to where the forest thins. Big Meadows, a two-mile-long field flanked by spruce and filled with a dozen varieties of wildflowers (bloom starts in July) stays hidden until after the junction with the Green Mountain Trail.

TON004

Location: 40.310471, -105.812335

Bear right and stay on Tonahutu Creek Trail at the junction with Green Mountain Trail.

TON005

Location: 40.320799, -105.810576

Bear right at trail fork.

TON006

Location: 40.319294, -105.772458

Pass 30-foot Granite Falls.

TON007

Location: 40.331693, -105.748773

Turn left onto the Hynach Lakes Trail to spend the night at Hynach llama camp.

TON008

Location: 40.335394, -105.754653

Located at 10,707 feet in a pine-bottomed valley, this campsite offers a surround-sound wilderness experience—a rushing stream, yipping coyotes, and bugling elk. Next day: Return to the Tonahutu Trail junction early the next morning (by 7 a.m.) to avoid summer’s afternoon thunderstorms on the exposed alpine miles ahead, and ascend across granite talus to Bighorn Flats.

TON009

Location: 40.32963, -105.734742

Mountain views open to the west on this treeless slope. Climb toward Ptarmigan Point (12,363 feet) on the Continental Divide.

TON010

Location: 40.310784, -105.701174

Ptarmigan Pass

TON011

Location: 40.309534, -105.694771

Turn right onto North Inlet Trail at this 3-way junction. The trail continues south past knee-high cairns with eastern views of 14,259-foot Longs Peak. Optional: Drop your pack and hike to the rock-lined rim at Flattop’s 12,324-foot summit above Emerald Lake.

TON012

Location: 40.285485, -105.693971

At mile 15.7, descend 1,400 feet in 1.3 miles on switchbacks to Hallett Creek.

TON013

Location: 40.286764, -105.702855

Cross Hallett Creek.

TON014

Location: 40.281389, -105.721397

Continue straight at this junction. After North Inlet Junction campsite, there’s a second string of camps. Aim for the dispersed zone south of 60-foot Cascade Falls.

TON015

Location: 40.271441, -105.766538

Arrive at Cascade Falls.

TON016

Location: 40.26394, -105.788775

The trail skirts Summerland Park as you knock off the final three miles between high and home.

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