Are dogs allowed on Thornton Lakes Trail?

Yes, dogs are allowed on Thornton Lakes Trail but must be kept on a leash at all times. Pack out waste and respect wildlife.

Do I need a permit to hike Thornton Lakes Trail?

No, Thornton Lakes Trail does not currently require a permit. Still check for seasonal closures or day-use fees with the managing agency before heading out.

How difficult is Thornton Lakes Trail?

Thornton Lakes Trail is rated expert. It is 8.3 miles long with 4,016 feet of elevation gain. Difficulty ratings reflect a combination of distance, elevation gain, and terrain — your experience will depend on your fitness level and trail conditions.

What is the best season to hike Thornton Lakes Trail?

Thornton Lakes Trail is best hiked in summer and fall. Conditions vary year to year — check the trail status and weather forecast before your visit.

Is Thornton Lakes Trail suitable for kids?

Thornton Lakes Trail is not typically recommended for young children due to length, exposure, or technical terrain. Older kids with hiking experience may be fine — use your judgment based on your family's comfort level.

Status unknown — verify before visiting

We don't have current condition data for this trail. Check with the land manager before you go.

See Washington trail conditions

ExpertOut and Back

North Cascades National Park/Washington

Thornton Lakes Trail

Marblemount, Washington

8.3 mi

Distance

4,016 ft

Elev. Gain

4h 19m

Est. Time

Out & Back

Route Type

Expert

Difficulty

About This Trail

The Thornton Lakes Trail is a challenging 8.3-mile out-and-back trail located in North Cascades National Park near Marblemount, Washington. This trail features a significant elevation gain of 4,016 feet, making it suitable for experienced hikers. The trail climbs through forested areas, offering hikers a chance to explore the rugged beauty typical of the North Cascades region. As the trail ascends, it provides impressive views of the surrounding mountains and valleys. The endpoint at Thornton Lakes offers a rewarding view and a sense of remoteness that characterizes the park.

Trail Conditions

Unknown

We have no current condition data for this trail. Check with the operator before you go, and submit a report below if you've been recently.

No recent condition reports. Be the first to share what you see on the trail.

Hazards & Warnings

steep elevation gainrugged terrain

Elevation Profile

Min:771 ft

Max:1,526 ft

1,224 ft

Trail Details

Dogs on leash

Route Type: Out & Back
Surface: Dirt

Official sources & verification

Managed by United States Forest Service

Verify before you go

Verify by phone or mail

Address:WA

Best Seasons

Summer Fall

Highlights

forest settingmountain viewslakes

Reviews

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Legacy import — verify before navigating

Path geometry came from our pre-launch legacy database. Routes have not yet been re-verified against the operator and may differ from the actual trail.

Hunt context