Lost Twin Lakes from West Tensleep

Cloud Peak Wilderness, Bighorn National Forest (West Tensleep Trailhead north of Ten Sleep)

Lost Twin Lakes sit in a cliff-walled cirque on the west side of the Cloud Peak Wilderness. A 2022 trip report describes the setting as a valley enclosed by cliffs about 1,000 feet high on three sides.

The trail starts at West Tensleep, which the Forest Service calls one of the most heavily used trailheads in the area, and covers about 11 to 12 miles round trip.

The hike

Lost Twin Lakes Trail #65 leaves the West Tensleep Trailhead, at the end of West Tensleep Road, at about 9,100 feet. ETB Travel Photography, a 2023 blog post, describes the trail climbing through evergreen forest, dipping, and then climbing steeply, with views around mile two and a creek crossing just past a small waterfall.

Around mile three a faint path leads to Mirror Lake, hidden in dense forest. ETB says many hikers turn around there. A Backcountry Post trip report from Labor Day 2019 says the main trail doesn’t reach the lake, which can be seen through the trees, and that several hikers had missed it.

Beyond, the trail drops into a valley of wildflowers, crosses a second narrow creek at about 4.5 miles, and passes through willow meadows before a final half-mile climb to the lakes, per ETB. The 2019 report put the lakes at about 10,300 feet, roughly 1,200 feet above the trailhead, and logged 7.0 miles one way, including wandering to find a site. ETB estimates about 2,000 feet of gain and rates the trip “Hard due to length.”

The lower lake gets most of the campers. The 2019 report says the group went over a saddle to the upper lake, an easy route toward the high country to the north-northeast, and heard from an angler that the upper lake fished better, probably because fewer people camp there. Everyone they spoke with had caught fish.

The 2022 group summited Bighorn Peak (12,324 feet) from their camp, leaving at 5:30 a.m. and reaching the top about 7:45. Both reports describe moose near the lakes and trail.

For a longer trip from the same trailhead, see Mistymoon Lake and Cloud Peak or the Solitude Loop.

Tips

Register at the trailhead kiosk. It’s required and free.
Avoid holiday weekends if you can. The 2019 group struggled to find legal parking and found campsites crowded.
Bring waste bags. Human waste must be packed out in the West and Middle Tensleep drainages.
Use a stove; no fires above 9,200 feet.
Give moose space, especially cows with calves.

Camping

Bighorn National Forest order 02-02-26-01 (March 31, 2026, through 2030) requires a free, signed and dated self-issued registration for every visit. Groups are limited to 10 people and 15 head of stock. Camping is prohibited within 100 feet of any lake, stream, or pond. Above 9,200 feet only self-contained chemical stoves are allowed. Solid human waste must be packed out of the West and Middle Tensleep drainages in a leak-proof container.

Below the trailhead, order 02-02-01-25-02 prohibits camping along Forest Road 27 from Tyrrell Ranger Station to the wilderness boundary, outside developed campgrounds, and limits fires to Forest Service metal rings there.

Inside Intel: The 2022 Backcountry Post group camped on the far right shoreline of Lost Twin Lakes and watched a bull moose graze by the waterfall at sunset. The 2019 report suggests the upper lake for fewer neighbors; its author camped at the lower lake after wandering to find a site away from others.

Trail facts

Distance: 11-12 miles round trip (ETB Travel Photography)
Route type: Out and back
Difficulty: Moderate to hard
Elevation: About 9,100 feet at the trailhead to about 10,300 feet at the lakes
Campsites: Dispersed; lower and upper lakes
Water: Creeks and lakes; treat it
Permits: Free self-issued registration required
Fires: Chemical stoves only above 9,200 feet
Human waste: Pack out in the West and Middle Tensleep drainages
Trailhead: West Tensleep Trailhead, end of West Tensleep Road (FSR 27)
Last verified: October 12, 2026

The Lowdown

Cliffs on three sides at Lost Twin Lakes:

One 2022 trip report describes this lake basin at about 10,300 feet as walled by roughly 1,000-foot cliffs, with a brief shower the morning they hiked in. See the backpacking tents testers trust.

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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.