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.