- 20 miles west of Boulder
- 2.6 or 5 miles oneway
- Trailhead Elevation:
- 10100 feet
- Elevation Change:
- 1300 feet
- June - October
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, Middle Boulder Creek for about a half-mile, dropping down to cross the stream on a narrow bridge near a scenic waterfall. It's about a mile from the stream crossing to Diamond Lake, a very popular camping area with limited designated campsites. This stretch of trail is on a northeast facing slope and holds snow long after the Arapaho Pass Trail has melted dry. 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 less traveled. The drop from the ridge back to treeline has been recently re-located to reduce erosion on the steep slope, and may be difficult to find. There are a couple cairns at the edge of the trees, and it is well worth finding the good trail that cuts across a 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.
Length: 4th of July TH to: Diamond Lake - 2.6 miles; Devil's Thumb Trail - 5.0 miles. DISTANCES ARE ONE-WAY.
2.6 miles oneway to Diamond Lake
5 miles oneway
From Nederland, west of Boulder, turn west on paved County Road 130, following signs for Eldora Ski Resort and the town of Eldora.
Go through the town of Eldora.
At the end of town, continue westward as the pavement ends, following to the right at the next road fork. Another 4 miles brings you to the Fourth of July Trailhead. This portion of the road is rough but 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.