Page Type Page Type: Mountain/Rock
Location Lat/Lon: 47.50780°N / 121.7389°W
Activities Activities: Hiking, Trad Climbing, Mixed, Scrambling
Seasons Season: Spring, Summer, Fall, Winter
Additional Information Elevation: 4167 ft / 1270 m
Sign the Climber's Log


With an estimated 80,000 to 100,000 visitors each year, Mount Si is arguably the most heavily climbed trail in the entire state of Washington. Mount Si is used by a wide variety of people- hikers, climbers, trad climbers, trail runners, people training to climb Rainier, and even mixed climbers in winter. It is not uncommon to see paragliders who have used Mount Si as a launching pad, either.

The trail begins at an altitude of approximately 700 feet, in a conifer forest which still shows traces of the last forest fire to sweep through in 1910. After 900 feet of elevation gain over the first mile, you’ll reach a rocky area with views of the valley to the south. At the two mile mark, you’ll arrive at “Snag Flats”, altitude 2,100 feet- the only flat section of the entire trail. There is a short interpretive boardwalk at this point that describes the natural history of the area.

From Snag Flats, ascend an additional 1,800 feet to Haystack Basin, elevation 3,900 feet. With sweeping views to the south, the Olympics to the west and a good view of Seattle on a clear day, the basin is where most people call it a day. If you’re feeling adventurous, continue up the trail just a few more minutes to the Haystack.

The Haystack has a few rock routes on its southern and eastern flanks, and on the north side, there is a route to the top that can be scrambled. The summit scramble is not for everyone. This can’t be stressed enough. A fall off of the Haystack is going to be an uncontrolled fall. People have been seriously injured, and in some cases people have died scrambling to the top. Use extreme caution when making the scramble, and if it’s foggy or raining, seriously consider coming back another day. Different sources give the height of the Haystack at between 300 and 500 feet.

Mount Si is the most obvious peak on a ridge that also contains Little Si, Peak 4560, Mount Teneriffe, and Green Mountain. There is a very faint climbers trail near the Haystack that trends northeast along this ridge. For more info, pick up the “Mount Si” USGS map, or Green Trails map No. 206S.

Roundtrip, you’ll hike eight miles if you stop at Haystack Basin, eight and a half if you continue to the summit. Average roundtrip time is about five to seven hours.

Two interesting pieces of side information: Mount Si is named for Josiah “Uncle Si” Merrit, a farmer who settled at the base of the mountain and built a cabin in 1862. Regional Native Americans called the mountain “Kelbts”.

Getting There

Getting there depends upon your needs- whether you need to make a pit stop for food or supplies or not. If you need to make that pit stop, take exit #31 from I-90. From the west, drive around the roundabout to your left, heading north into town. From the east, take a right off of the exit, heading north in to town. You’ll find fast food and gas stations right off of the highway. Continue driving north on North Bend Blvd/Bendigo Blvd S/ SR202; at E North Bend Way/432nd Ave SE, take a right. In 0.6 mile, turn left on SE Mt Si Rd. Arrive at the signed turnoff for the traihead on the left in a little over 2 miles.

If you’re ready to go, and you want to go straight to Mount Si, take exit #32, the 436th Ave SE exit, from I-90. If approaching from the west, turn left and head north. If approaching from the east, turn right and head north. Continue driving about .5 mile to SE North Bend Way. Turn left, and drive west .25 mile, and turn right onto SE Mt. Si Rd. Arrive at the signed turnoff for the traihead on the left in a little over 2 miles.

Red Tape

Parking at the trailhead is on a first come, first served basis, and is free. Although the parking area can hold approximately 200 cars, it is not uncommon to find the lot completely full, especially in summer. Effective 7/1/2011, a Washington State Discover Pass is required to park at Mt. Si. A one day Discover Pass is $10 but costs you $11.50 in most cases, an annual Discover Pass is $30 but costs you $35 in most cases. Enforcement will be very strong with this pass, do not risk parking without it. The fine for non-compliance is $99. Water and toilets are found at the trailhead. Dogs on leashes are allowed on the trail- don't forget to scoop up after them!

When To Climb

Thanks in large part to Mount Si’s proximity to civilization, as well as the low altitude of the trailhead, it is climbed year round. For winter climbing, crampons and/or snowshoes may be necessary in heavy snowpack years; in average to light snowpack years, microspikes or Yaktrax are generally a good idea. The last 1,000 feet get packed down and iced over, making for slow going over slick terrain if you aren't prepared.


Because Mount Si is within the Mount Si Natural Resources Conservation Area, camping is not permitted within the park. The nearest "official" camping is at the Denny Creek Campground, 15 miles further east on I-90.

External Links and Additional Information

No description of Mount Si would be complete without mentioning a site with a pretty sweet webcam focused on Mount Si. The pictures are also compiled into an amazing 24 hour timelapse movie. (The timelapse movie may appear to be dark for some time, but it isn't broken, it's just dark outside. Make sure to watch the whole movie!) Webcam and timelapse movie courtesy William Carrel.

For additional information, contact the Washington State Department of Natural Resources, South Puget Sound Region at (360)825-1631.

The short story of the creation of Mount Si, according to the Suquamish Tribe, can be found in "Indian Legends of the Pacific Northwest", by Ella E. Clark. (This book, incidentally, discusses the creation of many of the Pacific Northwest's mountains, according to local tribes, and is a fascinating read.)



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