Devils Thumb Trail to Diamond Lake, Hessie Trailhead, Indian Peaks Wilderness Area, Colorado

Devils Thumb Trail to Diamond Lake - 12.45 miles

Hessie Trailhead

This alternative route to Diamond Lake passes through lengthy stretches of open tundra

This alternative route to Diamond Lake passes through lengthy stretches of open tundra

Round-Trip Length: 12.45 miles
Start-End Elevation: 9,009' - 10,940' (11,510' max elevation)
Elevation Change: +1,931' net elevation gain (+3,327' total roundtrip elevation gain)
Skill Level: Strenuous
Dogs Allowed: Yes
Bikes Allowed: No
Horses Allowed: No
Related Trails:

Devils Thumb Trail to Diamond Lake - 12.45 Miles Round-Trip

While most hikers access Diamond Lake from the Fourth of July Trailhead, a longer and commensurately rewarding alternative begins at the Hessie Trailhead. This strenuous route follows the Devils Thumb Trail to the Diamond Lake Trail, which scales the north valley wall and drops to Diamond Lake in the adjacent valley.

Trail Map | Photo Gallery

Visitors will enjoy stunning alpine scenery and light crowds much of the way. The segment between the Devils Thumb Trail and Diamond Lake is exposed and steep with some potentially vague stretches. Allow extra time for the return, which requires a demanding climb back over treeline:

The trail begins on a steep dirt road lined with aspen and wildflowers, merging with the South Fork of Middle Boulder Creek at the Devils Thumb Bypass Trail split (.85 miles : 9,455'). Bear right on the Devils Thumb Bypass Trail.

Moderately steep switchbacks twist through dense forest to a broad meadow ringed by aspen and braided with streams (1.25 miles : 9,625'). This is a good place to find wildlife.

The trail levels past the Wilderness Boundary (1.4 miles : 9,650') back into the forest (1.65 miles).

A moderate, rocky path climbs through intervals of meadow and forest to the Devils Thumb Trail - Woodland Lake Trail split (2.2 miles, 9,792'). Veer right toward Jasper Lake on a steeper grade that can be obscured by runoff and snow through early summer.

Be patient with route finding and ignore social trails that ostensibly offer an easier way. Anticipate one sudden, poorly marked left turn over a tributary at 2.85 miles (10,215').

The trail climbs methodically to the Diamond Lake Trail split (3.75 miles : 10,675'), which bends northeast on a winding, strenuous push through treeline. A thinning forest yields sweeping views and useful perspective on the valley through which you've passed. These high open slopes are a good place to see elk in peak summer months.

The trail negotiates a final band of spruce (4.25 miles : 11,095') before clearing treeline (4.35 miles : 11,135'); once through it fades with only a series of large, spaced-out cairns for guidance. The trail gradually curls N-NW with terrific views of the Diamond Lake valley.

The trail eases to its high-point (4.65 miles : 11,510') and a divisive saddle between the valleys (5.0 : 11,450'). Here it drops steeply north on rugged, ill-defined switchbacks. Remain vigilant on this descent.

The trail enters a reconstituting forest (5.4 miles : 11,020'), bends northwest and begins a shifting, undulating course to the lake. It crosses a marsh on wooden planks (5.55 miles : 10,980') and continues unevenly in a pristine forest.

Small glades and the sound of rushing water mark the final approach - follows signs across the outlet stream (6.15 miles : 10,930') to Diamond Lake (6.22 miles : 10,940').

Diamond Lake occupies a large, flat basin near treeline. Follow campsite access trails around Diamond Lake to views across the basin and Continental Divide, or up the north shore to its inlet, which you may follow on a x-country route to Upper Diamond Lake.

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Interactive GPS Topo Map

Key GPS Coordinates - DATUM WGS84

  • N39 57.100 W105 35.696 — 2WD Parking Area for Hessie Trailhead
  • N39 57.278 W105 36.192 — Hessie Trailhead
  • N39 57.330 W105 36.780 — .85 miles : Devils Thumb Bypass Trail junction
  • N39 57.364 W105 37.187 — 1.25 miles : Enter Meadow
  • N39 57.543 W105 37.547 — 1.65 miles : Exit Meadow
  • N39 57.848 W105 37.935 — 2.2 miles : Woodland Lake Trail junction
  • N39 58.133 W105 38.434 — 2.85 miles : Turn left over small creek
  • N39 58.475 W105 39.107 — 3.75 miles : Diamond Lake Trail junction
  • N39 58.625 W105 38.686 — 4.25 miles : Spruce stand before treeline
  • N39 58.785 W105 38.698 — 4.5 miles : Travel through tundra
  • N39 59.067 W105 38.597 — 5.0 miles : Crest saddle, begin descent to Diamond Lake
  • N39 59.240 W105 38.513 — 5.25 miles : Nearing treeline on north valley wall
  • N39 59.392 W105 38.499 — 5.55 miles : Cross footbridge through marsh
  • N39 59.632 W105 38.834 — 6.15 miles : Cross Diamond Lake outlet stream
  • N39 59.649 W105 38.945 — 6.22 miles : Diamond Lake

Worth Noting

  • Get an early start to avoid afternoon thunderstorms. Factor in nearly two miles and a 600' climb back to treeline on the return. Be mindful of changing weather patterns and plan travel time accordingly. If weather discourages you from the exposed return, consider continuing onto the Fourth of July Trailhead (2.65 miles) and walking the dirt road back to Hessie.

  • Mid-July is peak wildflower season in the Indian Peaks. Columbine are notably abundant along this route.

  • Look for elk, pika, ptarmigan and marmot near and above treeline.

Camping and Backpacking Information

  • Permits are required for all overnight campers June 1 - September 15.

  • Permits are required year-round for day and overnight use by large groups (8+) or organizational groups such as scouts, churches, schools and hiking clubs.

  • Group size is limited to 12 people or people and packstock combined.

  • Campfires are prohibited east side of the Continental Divide, as well as Caribou Lake, Columbine Lake, Gourd Lake, Crater Lake and in the Cascade Creek drainage above Cascade Falls.

  • Pets must be on a handheld leash at all times.

  • Camping is permitted only at designated campsites in the Diamond, Jasper, Crater and Caribou Lakes Backcountry Zones.

  • Camping is prohibited in the 4 Lakes Backcountry Zone (Mitchell, Blue, Long, Isabelle) May 1 - Nov 30.

  • Camping is prohibited within 100' of lakes, streams and trails.

  • Packstock are prohibited in the Four Lakes Backcountry Zone, in the Cascade Backcountry Zone above Cascade Falls and on the Diamond Lake Trail #975.

Fishing Information

  • Fishing is permitted at Diamond Lake with a current fishing license. Rainbow, Cutthroat and Brook Trout are stocked. Arrive early to avoid crowds.

Directions to Trailhead

Diamond Lake is accessible from the Hessie Trailhead in the Indian Peaks Wilderness near Nederland, Colorado.

From downtown Nederland, go south on Highway 72 for .5 miles to County Road 130 and make a right. You will see a sign for Eldora Ski Resort at this junction. Continue on Highway 130 through the town of Eldora, just past which it becomes a dirt road (4 miles).

2WD drive conditions end 4.8 miles from the Highway 72 turnoff. 4WD vehicles may veer left at this demarcation and continue another .5 miles to the trailhead. Others will have to park at one of the limited roadside spaces and walk the 4WD road to the Hessie Trailhead.

Contact Information

Boulder Ranger District
2140 Yarmouth Avenue
Boulder, CO 80301

Trip Reports

There are no trip reports on this trail.


"Definitely peak wildflower season! Beautiful and less-traveled way to get to Diamond Lake. Trail was in great shape - no snow fields to cross and very little mud and water except for the marsh right before the lake; I was fine in trail running shoes. However, if I were carrying a full pack, I'd want something with a sturdier sole. I took the free Hessie shuttle from the Nederland Park & Ride, which runs every 20 min from 8-8 (tips appreciated), hiked to Diamond Lake from the shuttle stop, then on to 4th of July TH and hitched a ride back to the shuttle stop. If you don't mess around exploring other trails and wondering around above treeline, I think this is a little over 9 miles."
Jen  -  Colorado  -  Date Posted: July 16, 2018


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