Ultimate Guide To Thornton Lake Trail in Washington For 2021

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The Thornton Lake Trail is a real treat for many hiking enthusiasts. The thrill of the trail is never complete without a taste of Thornton Lake Trail and Trappers Peak. Reserved for hiking only, you will need to cover a total distance of 5.3 miles (8.4 km) of hiking to the peak and then to the lake.

While scaling the ridge, you need to gain 2,400 ft (731m), after which you have to lose about 500 – 600 ft to reach the lake. Expect the hike to be moderately strenuous but worth the sweat.

The Thornton Lake Trail is most appropriate for one-day hikes or overnight camping. The area offers several off-trail exploration opportunities. For the first two or so miles (about 3.7km), the trail takes you through a moderate grade of an old road, which cuts through a forested stretch.

The stretch used to be a logging area in the 1960s, before the establishment of the present park. You are likely to find the road to be mostly brushy due to new growth. What is more, some sections of the road are steep and rough, hence may not be user-friendly for trailers or low-clearance vehicles. 


Consequently, you are advised to drive slowly on this road. The Thornton Lake trail will then take you through a steady climb, going through a forest made up of a natural mixture of matured hemlock, Douglas-fir, cedar, Pacific silver fur, maples, and alder. The forested area goes all the way until you reach meadows of huckleberry and heather, just before arriving at the top of the ridge. 

From the ridge-top, you will be sure of having spectacular views of Thornton Lake trail and Triumph Peak. The descent to the lake is not only steep but normally muddy and slippery. To reach the camp, you need to carefully hop on some rocks and floating logs, to get across the lake’s outlet.

NOTEIf you are out to spend your night in this spot, you are advised to get a backcountry permit from the local authorities, particularly the Marblemount Ranger Station. The overnight stay should be at a designated site within the Thornton Lakes areas and the permits are normally limited. The Lower Thornton lake has three camping sites, and during busy seasons, the sites usually fill quickly. Camping is prohibited on Trappers Peak, as well as on the ridge above the lake, and at the second lake. If you are headed for Triumph Peak, you might get a permit allowing you to use the triumph Col cross-country zone for camping.  


Thornton Lake Trail and Trappers Peak

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Trappers peak is the embodiment of the remoteness and jaggedness associated with the North Cascades. Although you must put in a lot of work on the trail, the result is always rewarding and worth your trouble.

If you begin your journey in Marblemount, you should hit the North Cascades Highway (Popularly known as Highway 20) and drive for 11 miles to the east. Between mileposts number one hundred and seventeen and one hundred and eighteen, turn left and take the Thornton Lakes Road. Continue down the sometimes-uneven gravel road for approximately five miles before reaching the trailhead at the end of the road.


Once you are at the lowest Thornton Lake Trail, you can choose to either relax by the pristine mountain waters or trudge on following the rocky ridge on your way to Trappers Peak. Whichever of the two options that you settle for, you will be in for a memorable adventure.


Navigating the Thornton Lake Trail

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The Thornton Lake Trail begins discreetly, meandering through the hillside forest and traversing a few creeks while gaining negligible elevation. At a closer look, you will see leftovers of the old logging road that your hike follows as you navigate the initial two miles. Once you are at the tail end of the road, the trail switches to the left and starts gaining some elevation. This stretch takes you through a densely forested area, and you need to walk carefully to avoid the several roots extending into the trail.

At approximately four miles, you will arrive at the North Cascades National Park, where your trail will keep climbing till you reach a signed junction. At this point, you will need to choose between spending some quality time beside the lake or keep ascending to savour extensive panoramic sights.

If you settle for the lake, turn to the left of the junction and head downhill for about half a mile to access the lowest Thornton lake trail. On the other hand, if you opt to continue ascending to the peak, turn to the right and prepare yourself to attain more elevation. For you to ascend to Trappers Peak, you will need to gain about 1000 feet in under a mile, before you begin savouring the amazing views. 

From here, you can see the Skagit Valley and Teebone Ridge. A scrambling route will take you through a steep climb leading to Trappers Peak from where you can have clear views of all three Thornton Lakes trails. The main trail goes on to a smaller ridge that offers amazing views of the first lake as well as the Triumph Peak yonder. 

The Thornton Lake trail is rugged on your way to the peak and sometimes may need you to use your hands to support the climb. There might be nothing much in terms of exposure, but you will have to be very careful in your footing since there are parts where a small misstep might send you precariously tumbling downhill.

However, once at the peak (slightly below 6,000 feet), you will relish in extensive views of some of the best North Cascades attractions. You will see, right before you, the Picket Range with all its spiky, dagger-like tops and picturesque glaciers. To the west, you will have Mount Triumph looming, besides having a wonderful sight of the upper Thornton Lake trail way below.

On turning around, you’ll be met with remarkable sights of the Skagit River, with vast farmlands stretching all the way to the farthest horizon. You can also see the town of Newhalem snuggled beside Highway 20 (popularly known as the North Cascades Highway).

A steep 1km descent from the saddle takes you to the lower Thornton Lake trail. Above the first lake are two more lakes, each cupped a separate rocky basin. The two lakes were made as glaciers dug out rock basins, after which they were re-treated. This area is known to have an abundance of wildlife. Be on the lookout for bears, deer, birds, and marmot. You can also observe eagles and hawks in the autumn migration.  

For more incredible hikes in North Cascades, check out our guide to Finding the 10 Best Hikes in North Cascades National Park.

If you’re planning a trip to North Cascades and are looking for a great place to stay, look no further than THE 6 BEST HOTELS NEAR NORTH CASCADES NATIONAL PARK.


Final Thoughts on Things to Take Note of

  • No fires are allowed within the area
  • You can only take your leashed pet as far as the boundary of the national park, just under the ridge. Pets are disallowed on the ridge, the Trapper peak, and at the Thornton Lake Trail. 
  • To cross the lake outlet, you will have to scramble on big, often slippery rocks and floating logs. 
  • The vegetation in this area is very fragile. During your hike, you are required to be careful not to trample on it, by resting only on strong surfaces like snow, rocks or the trail.
  • The Thornton Lake trail usually has sections of snow that might need you to carry an ice axe, during the early season.
  • To reach the trailhead, at times, you might be required to drive right through various snow-laden trees that line the roadside. When these trees are laden with fresh snow, you might encounter several low-hanging branches. This means that you need to drive carefully, especially if your vehicle doesn’t have an efficient collision detection mechanism. Despite the road being bumpy, it is passable.
  • Returning down to the trailhead might be a bit tricky. The overall steepness may pose a real challenge and other than sloppy snow, you are also likely to encounter snow-covered rocks. However, the gully is pretty short, with a vertical distance of about 100 feet. After the gully, going down to the trailhead is a bit easier.
  • On your way to the Thornton Lakes Junction, you are also likely to encounter snow all the way. In the beginning, the snow cover might be thin, but as you move closer to the junction the snow grows deeper and deeper. In such times, locating the route may prove to be a bit challenging, especially if there is no trace of previous tracks to follow, once you branch off the old logging road. Breaking through the ever-deepening snow might also prove to be quite a challenge.
  • Sometimes ascending the Trappers Peak may be strenuous, especially if you are unable to find the trail to the peak. In such circumstances, some hikers may opt to go cross-country following the ridge. This might make the ascent more challenging, especially if approach the ridge from a steeper, rocky and snow-filled side. As you approach the top of the ridge, more fresh snow might hinder your gain of more altitude, hence some hikers opt to out at about 5500 feet. However, the views from such altitude are, nevertheless, spectacular.

Next, check out the other top hikes in North Cascades National Park outside the Thornton Lake Trail by following the links below: