Diamond Lake (#975)

Photo of Diamond Lake in June frozen and covered with snow

Length: Fourth of July Trailhead (TH) to: Diamond Lake - 2.6 miles; Devil's Thumb Trail - 5.0 miles. DISTANCES ARE ONE-WAY.

Elevation: 10,100 feet at the Fourth of July TH; 10,940 feet at Diamond Lake; 11,400 feet at high point; 10,700 feet at Devil's Thumb Trail.

Trail Description: The Arapaho Pass Trail enters the Indian Peaks Wilderness and climbs for 1.2 miles to the Diamond Lake Trail.

The Diamond Lake Trail forks left from the Arapaho Pass Trail and drops elevation for a half-mile before crossing the North Fork of Middle Boulder Creek. Diamond Lake is located a mile further uphill from the bridge and scenic waterfall. This stretch of trail is on a northeast-facing slope and holds snow long after the Arapaho Pass Trail has melted dry. Turn west on a marked side trail to Diamond Lake.

Continuing straight and passing the turnoff to Diamond Lake, the main trail continues for 2.4 miles, and climbs up to cross the ridge just above tree line. The return to tree line may be difficult to find - watch for rock cairns at the edge of the trees. The Diamond Lake Trail ends at Devils Thumb Trail.

At a Glance

Permit Info: This trail lies within the Indian Peaks Wilderness Area:
  • Camping permits required for all overnight trips between June 1 and September 15. Overnight permits cost $5 per group, per trip from June 1 through September 15.
  • Organized groups are required to have a permit for both camping and day-hiking year round. Day-hiking permits are free.
Usage: Heavy
Best Season: Hiking conditions are best from July through October
Restrictions: Indian Peak Wilderness restrictions apply:
  • Motorized equipment and mechanized transportation are prohibited.
  • Pets must be on a hand-held leash at all times.
  • Campfires are prohibited year round.
  • Campsites must be at least 100 feet away from water and trails.
  • Camping at Diamond Lake is restricted to designated sites only.
  • Group size is limited to 12 (people and livestock combined).
  • Processed weed-free feed is required for stock.
  • Practice Leave No Trace principles.
Fishing and hunting: permitted in accordance with regulations established by the Colorado Parks & Wildlife.
Closest Towns: Nederland, Colorado
Water: Lakes and streams; treat water for drinking.
Restroom: Practice Leave No Trace principles
Operated By: U.S. Forest Service

General Information


From Nederland, head south on Colorado Highway 119 for 0.5 miles. Turn west onto Boulder County Road 130 (signed for Eldora Ski Resort). Stay on the main road through the town of Eldora. Once the pavement ends continue another five miles to the Fourth of July Trailhead. This portion of the road is rough but passable in a passenger car during the summer months. This trailhead is extremely busy, especially on weekends, and parking is limited.


Access to the Fourth of July Trailhead is via Fourth of July Road. This road is maintained by Boulder County. There is no seasonal gate on this road. However, winter maintenance does not occur. In addition, once the town of Eldora receives a significant snowfall, plows pile snow at the end of the pavement creating a barrier to points west. Therefore, access in the fall is weather dependent. The road is not passable in winter. Boulder County typically plows this road open before Memorial Day weekend. Trails at this elevation are typically not snow free until July.


Lake and Pond Fishing

Day Hiking


XC Skiing/Snowshoeing

Recreation Areas

Recreation Activities


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