Fern Lake

Fern Lake is a backcountry lake in the upper Big Thompson valley of Rocky Mountain National Park. From Fern Lake Trailhead, the NPS route is 3.8 miles one way with 1,375 feet of elevation gain. Plan on a 7.6-mile round trip. This is a full hike, not a roadside stop. The length and climb suit hikers who want a substantial outing and a high lake as the payoff.

The trail follows the upper Big Thompson River to The Pool, then climbs through spruce forest to Fern Falls and continues to the lake. The Pool and Fern Falls are separate stops along the way. The route continues around the east side toward Odessa Lake and Bear Lake; that longer point-to-point traverse is different from the Fern Lake out-and-back. Summer parking at Fern Lake Trailhead is very limited, so consider the Hiker Shuttle.

From the north shore, look across the lake toward Notchtop Mountain, Little Matterhorn, and Gabletop Mountain. For a photo that shows the setting, keep some of the lake in the foreground with the peaks beyond it.

The complete route was established by 1906. Fern Lake became a winter destination, and the Colorado Mountain Club held annual winter outings here from 1916 through 1934. During the Great Depression, Civilian Conservation Corps crews improved the route and built rock walls. Much of that work remains, and the trail reflects the National Park Service's naturalistic design of the 1920s through 1940s.

The 2020 East Troublesome Fire caused significant damage along the Fern Lake corridor. Burned forest is part of the route's more recent story, though the exact view changes as the area recovers.

A backcountry campsite north of the lake has one individual site and one group site. There is no privy; approved waste bags are required. Campfires are prohibited, and water from the lake's inlet or outlet streams must be treated. Bear-resistant food canisters are required from April 1 through October 31.