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Idaho Trails

Ketchum, ID: West Pass

This rigorous, 9-mile out-and-back near Ketchum travels to a scenic mountain pass in the heart of the Boulder Mountains.

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You’ll gain more than 3,000 feet of elevation in 4.5 miles on this popular trek to West Pass. Located north of Ketchum in the Boulder Mountains, the challenging dayhike showcases some of Idaho’s best alpine scenery and travels through mountain goat and elk habitat. From the trailhead, the route climbs gradually through dense stringer timber and streamside meadows along the North Fork of the Big Wood River. (You’ll also pass views of the ragged crest of the Boulder Mountains and marshy areas inhabited by croaking frogs and darting brook trout.)
Near mile 2, the trail turns sharply to the northeast and begins a sustained climb to West Pass through a thick forest of Douglas fir and aspen. The winding path skirts waterfalls, avalanche chutes and scree slopes before finally topping out at 10,030 feet on the windswept pass. Stop for lunch and soak up the 360-degree views of the Boulder Mountains. Look northeast to find the rocky, 11,714-foot summit of Ryan Peak, the tallest mountain in the Boulders, and a worthwhile scramble for hikers with a little extra energy to burn.
INFO: Sawtooth National Recreation Area, (208) 727-5000;
-Mapped by Jason Kauffman


Trail Facts

  • Distance: 14.5



Location: 43.853229, -114.436415

From the trailhead, hike uphill on the well-used trail that quickly enters a conifer forest.


Location: 43.856193, -114.436115

After cresting the first short rise, descend a steep slope through open forest. Ahead, the trail parallels the North Fork of the Big Wood River.


Location: 43.858158, -114.435782

Keep right at the 3-way junction. The equestrian path on the left crosses to the other side of the river.


Location: 43.865027, -114.435718

The North Fork of the Big Wood River narrows as you near its headwaters. Watch for the dark silhouettes of brook trout darting between the stream’s overhanging grass and brush.


Location: 43.874927, -114.440589

Bear right at the faint Y-junction in the middle of the grassy meadow.


Location: 43.877065, -114.437137

After climbing past a series of short switchbacks through thick timber, enter the first of several open slopes with views to the distant treeline.


Location: 43.87913, -114.434768

Watch and listen for the series of waterfalls across the chasm to the southeast.


Location: 43.879846, -114.433401

Enter a sub-alpine forest of large conifers that cover the steep mountain slopes above.


Location: 43.886264, -114.414861

Trail leaves the final patch of steadily diminishing sub-alpine fir trees. Watch for wildlife in the few wind-blown whitebark pine trees that dot the alpine slopes above.


Location: 43.893084, -114.417275

After cresting a few false summits, the trail finally tops out on West Pass. On a clear day, much of the roadless Boulder Mountains can be seen from this high-elevation vista. Make sure to take time to soak up the remote surroundings, then backtrack to the trailhead.

Lupine near West Pass

Location: 43.892125, -114.416771

Mid-summer lupine blooms near the summit of West Pass.

North Fork of the Big Wood River

Location: 43.864052, -114.435525

The North Fork of the Big Wood River flows beneath lush green hillsides in central Idaho’s Boulder Mountains.


Location: 43.879103, -114.434516

A cascade of waterfalls echoes off the surrounding hills.

Near Timberline

Location: 43.889839, -114.415848

Closeup of alpine ground cover near timberline.

Alpine Basin

Location: 43.891509, -114.416749

Large, unnamed alpine basin near the top of West Pass.

West Pass

Location: 43.892975, -114.417104

A Tibetan prayer flag waves in the wind at the summit of West Pass in Idaho’s amazing Boulder Mountains.

Views from West Pass

Location: 43.893068, -114.417136

Looking south from the summit of West Pass.

High in the Boulders

Location: 43.893122, -114.417179

Some of Idaho’s highest and most remote peaks are located in the heart of the Boulder Mountain range.

Descending West Pass

Location: 43.891942, -114.416664

Headed downhill from West Pass towards the North Fork of the Big Wood River.

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