Devils Thumb Lake

Devils Thumb Lake at a glance

Devils Thumb Lake is one of the bigger Indian Peaks day hikes you can pull off from the Hessie Trailhead: a genuine alpine lake above 11,000 feet, tucked in the upper valley below Devils Thumb Pass and the Continental Divide. It sits about a mile past Jasper Lake, so you earn it, roughly 10.5 to 11 miles round trip with steady climbing the whole way. The lake takes its name from the Devils Thumb, the granite spire that stands over the basin and lends its name to the pass on the Divide above. This is a full-day, real mountain outing, not a foothill stroll.

The hike from the Hessie Trailhead

From the Hessie Trailhead you cross the footbridge and pick up the Devils Thumb Trail (Trail #902), which climbs steeply for about half a mile on an old road. The Devils Thumb Bypass turns right, north, just before the second bridge; it's shorter and crosses open meadows above the creek, though it skips the junctions with the King Lake and Woodland Lake trails. The route enters the Indian Peaks Wilderness, and the Diamond Lake Trail forks right about half a mile before you reach Jasper Lake. Jasper Lake is ringed on three sides by trees with a steep ridgeline to the north. From there the trail continues roughly another mile up to Devils Thumb Lake, and a mile beyond the lake it tops out on the Continental Divide at Devils Thumb Pass.

Parking and the free Hessie shuttle

Parking is the catch, just like the other Hessie hikes. Space along Fourth of July Road (CR 111) west of Nederland and Eldora is very limited and allowed only in the designated spots between the signs. Because the trailhead is so busy, Boulder County runs a free seasonal Hessie Trailhead Shuttle on weekends and holidays, roughly late May through mid-October, with no passes, reservations, or fares. On a summer weekend it's genuinely the easiest way in. For the full breakdown of driving directions, shuttle stops, and where parking is and isn't allowed, see our Hessie Trailhead guide. In winter, access is typically from the town of Eldora instead.

Difficulty, elevation, and altitude

Plan for a strenuous day. From the trailhead near 8,640 feet you climb roughly 2,400 to 2,500 feet to a lake sitting above 11,000 feet, on rocky trail that steepens past the Jasper Lake junction and can hold snow and runoff well into midsummer. At this elevation even a moderate grade asks more of your lungs than it would lower down, so pace yourself, drink more water than feels necessary, and turn around with plenty of daylight to spare. If you're not yet acclimated to Colorado's high country, this is a hike to build up to, not your first day off the plane.

Dogs, permits, and wilderness rules

Dogs are welcome, with one firm rule: in the Indian Peaks Wilderness, pets must be on a hand-held leash at all times, from the trailhead all the way to the lake. For an individual day hike you don't need a permit. If you want to stay overnight, backcountry camping in the Devils Thumb zone requires a permit from June 1 through September 15, at $5 per group, per trip. Organized groups are the exception to the day-hike rule and need a permit even for day hiking. Standard wilderness rules apply once you cross the boundary, including camping set back from water and the trail, and no campfires.

Fishing and wildlife

Devils Thumb Lake is a small, roughly 11-acre alpine lake, and with a valid Colorado fishing license anglers can try for the cutthroat and brook trout that Colorado Parks and Wildlife occasionally stocks in these high lakes. The long walk in keeps the crowds thinner than at the shorter Hessie destinations. This is prime high-country habitat, so keep an eye out for pika and marmots in the rocks, elk and the occasional moose in the meadows, and raptors overhead. Give any wildlife plenty of room and keep your dog leashed and close.

Best season and time to go

Aim for July through September, once the high country has melted out and the free shuttle is running on weekends. The upper trail past Jasper Lake faces into shaded, rocky terrain that holds snow and runoff into early summer, and snow returns in the fall, so midsummer is the most reliable window. Start early: it's a long round trip, parking fills fast, and afternoon thunderstorms are common in the Colorado high country. You want to be off the exposed upper valley and heading down before the weather turns.

Nearby trails and guides

• Hessie Trailhead: the full rundown on parking, the shuttle, and every trail that starts here, including this one.
• Lost Lake via Hessie: the shortest, most family-friendly hike from the same trailhead, if Devils Thumb is more than you want.
• All hikes in Boulder: the full hiking hub, sorted by difficulty.

Recommended nearby

A few local spots we'd point a Devils Thumb Lake day toward.

Devils Thumb Lake FAQ

Sources

Facts on this page are drawn from these authoritative sources:

• US Forest Service: Devils Thumb Trail (Arapaho and Roosevelt National Forests)
• US Forest Service: Indian Peaks Wilderness (permits, dog and wilderness rules)
• Boulder County: Hessie Trailhead (parking and shuttle)
• Boulder Convention and Visitors Bureau: Hessie Trailhead Shuttle