Unicorn, Foss, Boundary & Stevens Peaks

A 50 foot, mid 5th class, rock climb on sound rock on the south boundary of Mount Rainier National Park. Views of Mount Rainier, Mount Adams, Mount Saint Helens, and sometimes Mount Hood. Ice axe and crampons often needed in July to climb up steep gully just beyond Snow Lake. Times: 4-6 hr trailhead to summit. Consider traversing to The Castle instead of descending the climbing route. A great first alpine climb.

getting there

From SR-7 in Elbe, turn east onto SR-706, both known as the National Park Highway. Continue through the Nisqually Entrance of Mount Rainier National Park. Be prepared to pay the fee just after entering the park. Drive ~17 miles towards Paradise, take the turnoff to Ohanapecosh, and continue ~3 miles to the Bench Lake Trailhead (4,500 ft), ~1 mi past Reflection Lakes.

If doing the Unicorn-Castle Traverse, leave a car at Reflection Lakes on your way to the Snow Lakes Trail head to avoid a mile of road walk at the end of the traverse.

Unicorn Peak (6,971 ft)

Hike the Bench Lake Trail 0.5 mi to Bench Lake, and then 0.75 mi to Snow Lake (4,678 ft). Pass Snow Lake, drift right onto boulder field and head up steep gully into a basin. Continue onto a steep snow or scree field. Continue up headed southeast to the notch at about 6,500 ft. When there is no snow, keep far left and above the scree, where a climber's trail exists. Cross the notch and continue up to the left on easy snow or 50 feet of Class 2-3 rock to the ridge. Follow the ridge to the false summit and on to the base of Unicorn. 

In early summer the step from the notch to gain the summit ridge can have a large moat.  An alternate ascent to bypass this step is to head east from the notch 0.5 mile staying below rock faces on your left to a large gap in the face. Head up through the gap and continue north to the summit ridge. This alternate is steep and has loose scree above the gap when the snow has melted off.


The tower is 50-70 feet tall with several short rock climbing route options. The most common is the direct south face (mostly Class 4 with some 5.6 moves).  Another good option is the slightly longer south east route (just around corner) which is mostly Class 3-4 with a 5th class move.


Descend the Climbing Route
Descend the climbing route. One long runner is needed for a 50 m rappel from the summit.

Traverse to the Castle
Follow the ascent route back to the base of the steep snow below the ridge notch and head southwest to gain the ridge that runs from Unicorn Peak to The Castle.  Follow the moderately angled snow ridge to the base of The Castle.  The normal route ascends the middle of the face to gain the ridge 50-60 feet to the north of the true summit. However, there are a number of low 5th class variations that can be made to reach the summit ridge to the climbers right of this route.  Once on the ridge scramble south traversing to the true summit, class 3.  Note it is very exposed in places and most students will want a rope for this traverse.

Descend via a short rappel to the base of the face.  Return to Reflection Lakes by descending SE 1/4 mile and scrambling down a short class 2 face to the slopes south of the Castle/Pinnacle ridge and following the climbers path at the base of the rock face west to the maintained trail at Pinnacle/Plumber saddle. Follow this trail back to Reflection Lakes.

If the slopes to Reflection Lakes are still snow covered, a much shorter, and enjoyable descent can be had by heading directly down NNW from the base of The Castle to Reflection Lakes. 


Unicorn Peak/South Side
Trailhead to Summit 4-6 2,600
Summit to Trailhead 2-4
Unicorn-Castle Traverse
Trailhead to Unicorn Peak 4-6 2,600
Unicorn Peak to The Castle 2-4 1,100
The Castle to Trailhead 1-2


Standard alpine equipment.


  • The road may not be open before late May—check with Rangers. If not open, park at Narada Falls, and allow time for the extra 6 mi approach.
  • Hard snow may linger in steep gully well into July.  Bring ice axe and crampons.
  • The approach to Unicorn is an abysmal steep, chossy and loose scree strewn exercise and is NOT recommended once snow cover has melted off.

Foss Peak (6,524 ft)

This is one of the very few peaks in the Cascades (or anywhere) named for a prominent local female businesswoman, Thea Foss, of Tacoma, who started what became the Foss Maritime Company in 1889. Hike the trail to Bench Lake Trail and then follow a boot path past the lake. Climb the gully until to the basin above 5,400 ft. Head toward the ridge and saddle at 6,150 ft and then head northerly toward the summit.

Boundary Peak (6,760 ft)

Hike the Bench Lake Trail past Snow Lake. At the upper basin of Snow Lake (4,715 ft, a tarn is present in summer), head up a gully on a bearing of 231°. In the upper gully at 5,215 ft, follow a bearing of 201° to the upper basin, and at 5,720 ft follow a bearing of 150°. At the saddle west of Unicorn, 6,605 ft, follow a bearing of 73° and then 155° at 6,880 ft to reach the shoulder of Unicorn Peak. Follow this ridge to the summit.

Stevens Peak (6,560 ft)

Hike the Bench Lake Trail past Snow Lake. At the upper basin of Snow Lake (4,715 ft, a tarn is present in summer), head up a gully on a bearing of 231°. In the upper gully at 5,215 ft, follow a bearing of 201° to the upper basin, and at 5,720 ft follow a bearing of 150°. At the saddle west of Unicorn, 6,605 ft, follow a bearing of 73° and then 155° toward Boundary Peak. At the low point on the ridge between Boundary and Unicorn Peaks, ~6,645 ft, descend steep terrain heading east 800 feet to the saddle at 5,800 ft between Stevens and Boundary Peaks. Ascend the ridge leading to the summit, staying on the south side.

Information for Leaders

  • This route allows multiple bookings. Please check scheduled trips listed below in the "Activities" tab to see if there is another group already booked on the same day. Leaders are expected to contact the leader(s) of existing trips to ensure there are no concerns or conflicts, according to The Mountaineers Outdoor Ethics Policy.
  • Suitable Activities: Climbing
  • Climbing Category: Basic Alpine
  • Seasons: May, June, July, August, September, October
  • Weather: View weather forecast
  • Difficulty: Basic Alpine Climb, Strenuous 1, Technical 1
  • Length: 5.0 mi
  • Elevation Gain: 2,600 ft
  • 6,917 ft
  • Land Manager: Mount Rainier National Park
    Mount Rainier Wilderness
  • Parking Permit Required: National Park Entrance Fee
  • Recommended Party Size: 12
  • Maximum Party Size: 12
  • Maximum Route/Place Capacity: 12
  • Green Trails Mt Rainier East No. 270
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.

  • Unicorn Peak
  • Unicorn Peak/South Side
  • Unicorn-Castle Traverse
  • Unicorn & Castle Traverse
  • Unicorn Peak & The Castle Traverse
  • Boundary Peak
  • Foss Peak
  • Foss Peak/Unicorn Creek
  • Stevens Peak
Mountaineers Beta & Brews: Basic Climbs 2021

A link to the YouTube video of The Mountaineers Beta & Brews: Basic Climbs 2021. The Tatoosh Mini-Traverse (Unicorn, Foss, Castle, Pinnacle) presentation by Paul Brown and Ben Chapman begins at ~26:20.

Log in and send us updates, images, or resources.