Arapaho-Roosevelt National Forest
Diamond Lake Trail #975

4th of July Trailhead to: (one way)

• Diamond Lake: 2.6 miles
• Devil's Thumb Trail: 5.0 miles

Elevations:

• 4th of July Trailhead: 10,100'
• Diamond Lake: 10,940'
• High point: 11,400'
• Devil's Thumb Trail: 10,700'

Use: Extremely Heavy

Rating: More Difficult

USGS Maps: East Portal and Monarch Lake Quads

Trailhead Location: From Highway 119/72, turn west on County Road 130, located just south of the center of the town of Nederland, and follow the signs for Eldora Ski Resort and the town of Eldora. At the fork in the road, keep right, and go through the town of Eldora. At the end of town, continue westward after the pavement ends, going right at the next fork in the road. Another four miles brings you to the Fourth of July Trailhead. This portion of the road is rough but sort of passable in a passenger car. This trailhead sees extremely high use, especially on weekends, and parking is limited. Plan to arrive early and watch for signs along the road indicating legal parking spots.

Follow the Arapaho Pass Trail #904 out of the trailhead, into the Indian Peaks Wilderness, for 1.2 miles to the Diamond Lake Trail. The Diamond Lake Trail forks left where the Arapaho Pass Trail takes a switchback to the right. It traces upstream along the North Fork of Middle Boulder Creek for about a half-mile, dropping down to cross the stream on a narrow bridge near a scenic waterfall. It is about a mile from the stream crossing to Diamond Lake, a very popular camping area with designated (but limited) campsites. This stretch of trail is on a northeast facing slope and holds snow long after the Arapaho Pass Trail has melted out. Past Diamond Lake, the trail continues for 2.4 miles climbing up to cross the ridge just above treeline.

The part of the trail beyond the lake is not often traveled. The drop from the ridge back to treeline has recently been relocated to reduce erosion on the steep slope and, consequently, may be difficult to find. There are a couple of rock cairns at the edge of the trees, and it's worth finding the good trail that cuts across the steep slope, dropping down through the trees. The Diamond Lake Trail joins the Devil's Thumb Trail 0.6 miles below Jasper Lake for access to Jasper Lake, Devil's Thumb and Devil's Thumb Lake.

Backcountry camping in the Indian Peaks Wilderness is by permit only. Permits are required for camping along this trail June 1 to September 15. Contact the Boulder Ranger District (303-541-2500) for information.