Alpine climbing NCCS rating
Grade IV
Elevation Gain
3,725.00 ft (1,135.38 m)
9.95 mi (16.01 km)
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The intimidating spire of 9,182-foot Mount Thielsen can be seen as you travel to the trailhead. Yet the peak is not as difficult to climb as it might look. In spite of its appearance, Mount Thielsen is a good choice for beginning climbers and day hikers looking to get on an exposed face.

From the Mount Thielsen Trailhead just off Highway 138 near Diamond Lake, it's a moderate hike to the intersection with the Pacific Crest Trail. The West Ridge Route begins here, and it is a Class II and Class III scramble up scree and slate-like talus to a point called "Chicken Ledge." From this point, it's only 80 feet straight up on Class IV pitch. Many people and teams choose to rope up at this point and use protection. This is not required, but it is a good practice depending on you comfort level. This last 80 feet is on rock that is more solid than in earlier segments, which makes climbing a bit easier.

At the summit you are rewarded with views north all the way to the Three Sisters, south as far as Mount Shasta, and closer views of neighboring Crater Lake and Mount Bailey. 

The mountain is also known as the "lighting rod" of the Cascades because it attracts lighting strikes like mosquitos to sugar water. Due to Mount Thielsen's stormy nature, there are a few portions along the trail where small downbursts (microbursts) from thunderstorms have caused larger areas of downed trees. Be vigilant and always be on watch for changing weather.

Logistics + Planning

Preferable season(s)




Parking Pass

NW Forest Pass


Non-technical climb. Great views from the summit, including Crater Lake. Easy trailhead access.


Weather can change fast. Trail can be crowded in summer months.

Pets allowed


Trailhead Elevation

5,439.00 ft (1,657.81 m)


Rock climbing
Big vistas

Typically multi-day




The 10 mile hike is average difficulty as far as mountains go. The final half mile is tougher with scree, boulder fields, and a 50 foot scramble to the top. About half people free climb it, and half use ropes as far as I have seen. The rock is a lot more solid than most crumbly cascades.

Here is a video about the mountain and making the summit.
Quite a fun little climb with spectacular views!
Beautiful day on this iconic mountain! Fun fact: the summit of Mt. Thielsen (pronounced TEEL-sun) is the only location you can see the waters of Crater Lake outside of Crater Lake National Park.

The final Class IV scramble is relatively easy to follow, yet might be uncomfortable for those not accustomed to Class V routes due to the exposure.
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