Thornton Lakes & Trappers Peak

A strenuous, 10.6-mile in-and-out day hike with 3,300 ft in elevation gain. The trail goes up steeply through forest to a rocky outcrop with amazing panoramic views of Mount Triumph, Mount Despair and the Picket Range.

getting there

Drive SR 20 to 11 miles east of Marblemount and turn north onto Thornton Lakes Road. Continue to the road's end and trailhead (2,600 ft).

on the trail

Hike the Thornton Lakes Trail climbing through forest to a ridge crest at 5,000 ft with views down to the Thornton Lakes and across to Mount Triumph.    The lakes can be reached by poor trail down 500 feet from the ridge, about 1.5 miles to the farthest upper lake.  But for the most stunning views, from the ridge crest follow a climber's track up the ridge to the summit of Trappers Peak, about 1.5 miles and 950 feet farther up.

  • Thornton Lakes: 10.2 miles round trip with 2,900 feet of elevation gain to a high point of 5,000 ft
  • Trappers Peak: 10.6 miles round trip with 3,300 feet of elevation gain to a high point of 5,964 ft
  • Thornton Lakes & Trappers Peak: 13.6 miles round trip with 3,800 feet of elevation gain to a high point of 5,964 ft


  • In some places the final section to the summit requires the use of hands, though not particularly difficult or exposed unless dangerous snow patches are present which they can be early in the season.  If you don't like the looks of the last section to the summit, extraordinary views can still be had partway up.
  • Suitable Activities: Day Hiking, Scrambling
  • Seasons: July, August, September, October
  • Weather: View weather forecast.
  • Difficulty: Very Strenuous
  • Length: 10.6 mi
  • Elevation Gain: 3,300 ft
  • 5,964 ft
  • Land Manager: North Cascades National Park
    Ross Lake National Recreation Area
  • Parking Permit Required: None
  • Default Party Size: 12
  • Maximum Party Size: 12
  • Green Trails Marblemount No. 47
  • Trails Illustrated North Cascades National Park
  • Red Marker
    48.652884, -121.325383
    48.652883838 -121.325383187
  • Red Marker
    48.688445, -121.322315
    48.6884447294 -121.322314739

Upcoming Activities

Alpine Scramble - Trappers Peak & X Mountain

Scrambling Trip
We'll also do Thornton Peak, camping 1 night at the lake
Difficulty: Technical 5, Strenuous 4
Sat, Sep 15, 2018 - Sun, Sep 16, 2018
7 participants
Registration opens Aug 20
Seattle Branch
Trip Reports

This is a list of titles that represent the variations of trips you can take at this route/place. This includes side trips, extensions and peak combinations. Not seeing a title that fits your trip? Log in and send us updates, images, or resources.

  • Thornton Lakes
  • Trappers Peak
  • Trappers Peak & X Mountain

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