Rocky Mountain National Park: Chasm Lake 

For the ultimate view of Longs Peak's 1,000-foot Diamond Face, climb to Chasm Lake on this 8-mile out-and-back that tops out above treeline.

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Author: MichMan01
Date: 19 Jul 2011 11:36:36 AM
Activity: Hiking
State: Colorado (CO)
Distance: 8.2 mi  (Change units)
Survey Elevation: Total Gain: 2623 ft
Total Loss: 2623 ft
Net Change: 0 ft
Difficulty: 4 / 10
USGS Topo Map: Longs Peak
Tags: Boulder, Colorado, Denver, Estes Park, Rocky Mountain National Park
Rating: Unrated   Rate it

From the Longs Peak Trailhead, follow a wide path that climbs steadily through ponderosa pine toward Chasm Lake and the summit of Longs. This trailhead is more remote than others in the national park, but as the gateway to the park's only fourteener, it can be a veritable highway of hikers in July and August.

Switchbacks occasionally edging mountain streams eventually reach treeline just past mile two. From here, the trail heads across a wide, rocky basin toward Longs Peak, which is now in view. Crest a small ridge at mile 3.2 this is a great place to drop your pack for a quick snack, photo op, and use the privy, if necessary. (Why not? It has no roof and a great view of Longs' 1,000-foot Diamond Face.)

From here, edge left down into the valley that leads up to the Diamond. In early to mid summer, cross a patch of snow on the descent to columbine-lined stream crossings in front of the patrol cabin that sits at the base of the class-II scramble. Chasm Lake is still out of view.

South of the cabin, scout out cairns on the rock above. Although other routes through the short cliff-bands are doable, the cairns mark the easiest route, and it's a good practice to stay on the designated trail.

In five or ten minutes, summit your scramble to impressive views of the Diamond and icy Chasm Lake at its base. Shoo away aggressive marmots and chipmunks as you search for climbers on the Diamond and Ship's Prow, to the left.

PERMIT: Overnight camping in Rocky Mountain National Park requires a backcountry permit. Check out the latest fees and more details at untry.htm.

MORE PARK INFO: Rocky Mountain National Park, (970) 586-1206;

-Mapped by Jenn Fields

TO TRAILHEAD: From Estes Park, take CO 7 E. Turn right toward Longs Peak Campground (marked by brown National Park sign). Turn left at the Y-junction, and park in trailhead lot.

Position Format: Datum:

Chasm Lake

Distance: 8.20 mi Points: 418
Total Time: none Speed: 0.0 mph Pace: 0:00 / mi
Active Time: none Speed: 0.0 mph Pace: 0:00 / mi
Chasm Lake

Points of Interest


Location: 40.271774, -105.556450 Altitude: 2943.91088867188
Trailhead and Longs Peak Ranger Station is well equipped with modern toilets, but can be very crowded on summer weekends.


Location: 40.274994, -105.564110 Altitude: 2947.263671875
Turn left at the Y-junction half a mile from the trailhead.


Location: 40.272994, -105.570524 Altitude: 3093.87231445313
Pass the spur trail that leads to a backcountry campsite.


Location: 40.273212, -105.580032 Altitude: 3242.85864257813
Cross an upper branch of Alpine Creek on two sturdy wooden bridges.


Location: 40.270432, -105.578568 Altitude: 3284.21997070313
Around 10,700 feet, the steep, stair-stepped trail crosses treeline. Look for the Twin Sisters across the valley.


Location: 40.270691, -105.581444 Altitude: 3316.40698242188
Lift your eyes off the trail and start watching for views of Longs Peak's Diamond Face to the southwest.


Location: 40.270828, -105.584282 Altitude: 3351.73315429688
Turn left at Y-junction following signs for Chasm Lake.


Location: 40.267544, -105.591400 Altitude: 3466.6123046875
Above treeline, the rocky path is cairn-marked in some stretches. Pass a cairn here.


Location: 40.265656, -105.592537 Altitude: 3528.60864257813
Turn left at this Y-junction. The well-traveled path to Longs Peak veers right at this point.


Location: 40.265625, -105.591949 Altitude: 3521.17163085938
Privy: This outhouse has excellent 360 views. Go even if you don't have to.


Location: 40.264179, -105.594810 Altitude: 3539.6728515625
Peacock Pool is the small lake to the south; Chasm Lake is out of view, beyond the moraine to the southwest.


Location: 40.258827, -105.600601 Altitude: 3535.83251953125
Bear left for yet another photogenic privy before your arrival at the lake.


Location: 40.258595, -105.601021 Altitude: 3538.69750976563
Patrol cabin: Hopefully you'll never need to meet the rangers that work here.


Location: 40.258172, -105.602818 Altitude: 3602.64453125
Chasm Lake: Bring binoculars to seek out climbers ascending the Diamond Face. Turn around and retrace your steps to the trailhead.

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