Backpack Trail Guide

Trails / Colorado / Rocky Mountain National Park

Fern Lake and Cub Lake Loop (Old Forest Inn and Fern Falls)

Rocky Mountain National Park, National Park Service (Moraine Park, west of Estes Park)

Along the Cub Lake loop in autumn
“Along the Cub Lake loop in autumn” by AmblingGent , Creative Commons

AllTrails calls the Fern Lake and Cub Lake Loop a great introductory backpacking loop in Rocky Mountain National Park. From the Fern Lake Trailhead at the west end of Moraine Park, the trail follows the Big Thompson River past Arch Rocks and The Pool to the Old Forest Inn campsites, with a short side trip up to Fern Falls. The return passes Cub Lake and its meadows.

You’ll need a wilderness permit and a reserved campsite, and dogs aren’t allowed on the trail.

The hike

The Denver Gazette describes the Old Forest Inn backcountry campsite as a two-site camping area at 8,400 feet off the Fern Lake Trail, near The Pool west of Moraine Park. It says the campsite sits in a spruce and fir forest on the site of the old Forest Inn, a hotel built in 1917 and torn down in 1959. It’s 1.7 miles from the Fern Lake Trailhead, with about 250 feet of elevation gain.

From the trailhead, AllTrails says the trail follows the Big Thompson River, staying near it until the confluence of Fern and Spruce Creeks at The Pool. Along the way you pass the Arch Rock boulders and the Arch Rocks wilderness campsites. The Denver Gazette’s directions: hike past Arch Rocks to The Pool, continue toward Fern Lake, and look for a junction on the right, or north, marked with a wood sign for Old Forest Inn.

AllTrails notes that you can also see the historic ruins of the Old Forest Inn from the trail.

Fern Falls is the side trip. AllTrails says the trail eventually climbs steeply to the cascades. A July 2026 reviewer found the first part of the trail fairly level, single track with some overgrown vegetation, and the last part a fairly strenuous climb over rocky terrain. The trail continues past the falls to Fern Lake and Odessa Lake, for those with extra time and energy.

AllTrails says Fern Lake’s north side offers views of Notchtop Mountain and the Little Matterhorn. For a longer trip, it lists a 12.7-mile “five lake” route from Bear Lake that passes the Sourdough campsite near Marigold Pond, then Two Rivers Lake, Lake Helene, Odessa Lake, and Fern Lake before descending past Fern Falls and Old Forest Inn.

The canister rule has a history here. The NPS says that in 2003, two men were seriously injured by a black bear at a designated campsite near Fern Lake, and that the park later required canisters across most backcountry sites.

The return follows the Cub Lake Trail. AllTrails’ guide describes the return leg along Cub Creek past a waterfall, meadow, and Cub Lake, and says the Cub Creek campsite sits just past the lake. To finish the loop, you walk a short stretch of Fern Lake Road. One reviewer called the mile along the road the least pleasant part.

Fire shaped this valley. Several reviewers note that a fire burned through the area, leaving many trees burned and the trail less shaded. One still found it pretty, especially on the Cub Lake side.

The Denver Gazette says deer, elk, moose, and black bears are seen in the river valley. It recommends getting water from Fern Creek and boiling or treating it.

AllTrails lists May through October as the best months for the loop and notes the area is popular for backpacking, camping, and fishing.

For another first-time overnight in the West, see Little Lakes Valley in California.

Tips

Camping

The NPS says a wilderness permit is required for all overnight camping in the park, and that each party is assigned one campsite. Your permit must be displayed on your pack while hiking and on your tent at camp, and a dash tag is needed for overnight parking. From April 1 to October 31, all food, scented items, and garbage must be in a hard-sided bear-resistant canister placed at least 200 feet from your campsite; hanging food isn’t allowed. Old Forest Inn has two sites, according to the Denver Gazette and AllTrails. AllTrails lists other campsites along the loop: Arch Rocks, Fern Lake, and Cub Creek.

Inside Intel: Old Forest Inn makes the loop an easy first night. It’s only 1.7 miles in, per the Denver Gazette, which leaves time to set up camp and make the short, steep side trip to Fern Falls. AllTrails’ backpacking guide suggests choosing either of the two Old Forest Inn sites or continuing to Fern Lake for a swim. On the way out, a reviewer recommends the Cub Lake side as the prettier half of the loop.

Trail facts

The Lowdown

A first night at Old Forest Inn:

An easy hike to a forest campsite is a great time to try out a new sleeping pad. See which pads testers recommend.

See the picks →

Where this comes from

This page draws on the sources below, along with other guides and trip reports. Links go to the original pages.

Before you go: This page is based on published trail guides, trip reports, and reviews, along with official park and agency information where we could find it. It’s meant to help backpackers discover new trails, not to replace current, official information. Conditions, closures, permits, campsites, and water sources change, and some details here may be out of date or wrong. Confirm everything with the managing agency and check current conditions before you head out, and don’t rely on this page alone for safety or navigation. Backcountry travel involves risk.