Chasm Lake, Longs Peak Trailhead, Rocky Mountain National Park, Colorado

Chasm Lake - 8.4 miles

Longs Peak Trailhead

Chasm Lake (11,803')

Chasm Lake (11,803')

Round-Trip Length: 8.4 miles
Start-End Elevation: 9,405' - 11,803' (11,823' max elevation)
Elevation Change: +2,398' net elevation gain (+2,456' total roundtrip elevation gain)
Skill Level: Moderate-Strenuous
Dogs Allowed: No
Bikes Allowed: No
Horses Allowed: Yes
Related Trails:

Chasm Lake - 8.4 Miles Round-Trip

Chasm Lake is located 4.2 miles from the Longs Peak Trailhead in Rocky Mountain National Park. It fills a deep cirque carved from the base of Mt Meeker (13,911'), Longs Peak (14,259') and Mount Lady Washington (13,281'). Longs Peak's iconic 'Diamond' rises 2456' above this striking alpine lake. Visitors will enjoy miles of open tundra and sensational views on the hike to Chasm Lake:

Trail Map | Photo Gallery

The trail climbs steadily from the Longs Peak Ranger Station through lodgepole, spruce and fir. Alpine Brook, largely concealed by timber, is the only notable feature before crossing the top of a long cascade at treeline (1.85 miles : 10,615'), where the forest is quickly reduced to bands of 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 and extreme weather limit growth at these elevations. Still, the tundra's nutrient-rich grasses, plants, and lichens support marmot, elk, bighorn sheep and mountain goat

The trail bends toward the Longs Peak diamond from the Battle Mountain Backcountry Campsite spur (2.45 miles : 10,956') to the Chasm Lake - East Longs Peak Trail split (3.25 miles : 11,518'). Stock is not permitted on the Chasm Lake Trail beyond this point.

The trail bears SW along the north wall of a deep gorge carved by Roaring Fork (Chasm's outlet) with views of Peacock Pool. It crests and drops across a steep slope to an alpine bench that spans the upper valley and separates upper and lower Columbine Falls (3.8 miles : 11,580').

This short segment is narrow, slanted and susceptible to slides. Traction devices are useful when snow-covered. The trail levels across this stream-crossed bench to the south side of the valley and Patrol Cabin (4.0 miles : 11,638'). Here the trail - more of a scrambling route chiseled from rock - climbs .2 miles to Chasm Lake.

Large boulders and uneven talus ring the lake, requiring some minor scrambling to the best viewpoints. An unimproved route circles Chasm Lake's talus-strewn north wall to the base of Mills Glacier, a shrinking remnant of the area's active glacial past.

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N40 16.330 W105 33.409 — 0.0 miles : Longs Peak Trailhead
  • N40 16.495 W105 33.852 — .45 miles : Estes Cone Trail split
  • N40 16.385 W105 34.228 — 1.1 miles : Goblins Forest Backcountry Campsite spur
  • N40 16.489 W105 34.662 — 1.5 miles : Cross footbridge, resume steady climb
  • N40 16.390 W105 34.805 — 1.9 miles : Cross waterfall on bridge
  • N40 16.240 W105 34.837 — 2.25 miles : Winding trail through krummholz patches
  • N40 16.251 W105 35.056 — 2.45 miles : Battle Mtn Backcountry Campsite spur
  • N40 16.092 W105 35.218 — 2.75 miles : Steady, steep climb through open tundra
  • N40 16.059 W105 35.464 — 3.0 miles : Pass through 11,300'
  • N40 15.934 W105 35.561 — 3.3 miles : Chasm Lake - East Longs Peak Trail split
  • N40 15.742 W105 35.945 — 3.7 miles : Begin cross from N to S side of valley
  • N40 15.530 W105 36.040 — 4.0 miles : Reach S side of valley; begin rock scramble
  • N40 15.511 W105 36.180 — 4.2 miles : Chasm Lake (11,803')

Worth Noting

  • The hike to Chasm Lake is very exposed. Get an early start to avoid afternoon storms. Anticipate changing weather throughout the day and carry versatile layers.

  • The first 3.25 miles are shared with hikers aiming for Longs Peak, and you're likely to see crowds no matter what time you start out. Crowds thin beyond the Chasm Lake - East Longs Peak Trail junction.

  • Parking is very limited at the Longs Peak Ranger Station. Additional parking is available along the roadside leading up to the trailhead, but is also quite limited.

Rules and Regulations

  • Stock is not permitted on the Chasm Lake Trail past the East Longs Peak Trail - Boulderfield split.

Directions to Trailhead

Chasm Lake is accessed from the Longs Peak Trailhead in Rocky Mountain National Park. The Longs Peak Trailhead is located 10 miles south of Estes Park off of Highway 7, between Estes Park and Allenspark.

From Estes Park, travel 9.1 miles south on Highway 7 to the Longs Peak Trailhead turnoff on the west side of the road. Follow the road .9 miles to the ranger station and trailhead. Parking is very limited, and the lot fills up early on weekends. Additional roadside parking is available. Campground parking for non-registered users is prohibited.

Contact Information

Rocky Mountain National Park
Visitor Information:

Backcountry Office:

Campground Reservations:

Emergency Dispatch:


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