Mount Si Main Trail

A moderate/strenuous 8-mile round trip day hike with 3,200 feet of elevation gain. This is a popular trail in the foothills that offers a good workout and views of Puget Sound and the Upper Snoqualmie Valley. Variations include the Talus Loop, "Double Si" or "Si, Si Again" conditioner, Blowdown Mountain, Crater Lake Mountain, and Dixie Peak.

Getting there

Take Exit 32 off of I-90 and turn left (north) onto 436th Ave SE. Drive 0.5 mile  and turn left (west) onto North Bend Way nd in 0.25 mile, turn right (north) onto Mount Si Road. Continue 2.5 miles and turn left into the large trailhead parking lot (600 ft).

PUBLIC TRANSPORTATION - TRAILHEAD DIRECT

On weekends and designated holidays, Trailhead Direct takes riders to three hiking destinations: Mount Si, Issaquah Alps, and Mailbox Peak. All buses are run by King County and regular fares apply, just like in the city. By establishing this service, Trailhead Direct aims to increase accessibility to local trails, limit vehicle congestion in trailhead parking lots, and reduce carbon emissions. If you will have a group of more than 10 people, please fill out this form to reserve seating.

on the trail

Mount Si (3,900 ft)

A moderately strenuous 8-mile round trip hike with 3,159 feet of elevation gain

The Mount Si "main" Trail begins at the far corner of the parking lot where just past the picnic area and outhouse. The trail is moderate for the first two miles and then steepens with more switchbacks until it ends in the meadow at the top.

The "haystack" jutting out of the meadow is the true summit and it can be scrambled. The route is challenging and exposed, and it' easy to send rock fall to unsuspecting hikers below, so this is not recommended.

The Talus Loop Trail makes an excursion off the main Mount Si Trail, reconnecting at Snag Flats.  It's 1.3 mi instead of the 1.0 mi if you were to stay on the Mount Si Main Trail.

"Si, Si Again" or "Double Si" Conditioner: Hike up the Mount Si Main Trail to the viewpoint near the summit, down the main trail, lunch in the parking lot, then a car shuttle to the Little Si Trail parking lot, up the Boulder Gardens/Old Si Trail to the viewpoint, down the  trail, car shuttle back to Little Si. Great for conditioning!  It's 16 miles and 6,400 feet of elevation gain.

scramble routes

blowdown mountain (4,560 ft) and crater lake mountain (4,351 ft)

a 12-mile round trip scramble with 4,400 feet of elevation gain, difficulty: strenuous 4, technical 2

From top of Mount Si continue on the path and road to where that road terminates northwest of Mount Teneriffe. Ascend past 4,440 ft, then follow the ridge northwest, descend west to a saddle, and then ascend continuing west to the summit of Blowdown Mountain. The views are not great, but in winter, this is all that daylight may allow. From Blowdown Mountain, travel north, descending to a saddle and then ascending to Crater Lake Mountain.

Dixie Peak (4,606 ft)

a scramble with 4,400 feet of elevation gain, difficulty: strenuous 4, technical 4

From top of Mount Si continue on the path and road to where that road terminates northwest of Mount Teneriffe. Ascend past 4,440 ft, then follow the ridge northwest and then north to Dixie Peak.

INFORMATION FOR LEADERS

scheduling & permits

  • Permits are required in this area for all fee-based (course-related) activities, regardless of group size, and all free activities involving 13 or more people. Leaders may list trips at this route/place with the understanding that they need to verify that a permit has been obtained before running the trip (if required as outlined above). Permit applications are submitted to WA Department of Natural Resources annually in December. Please contact info@mountaineers.org with any additional questions. More details about permitting on WA DNR land as it applies to Mountaineers trips, as well as our current year Land Use License, can be found here.
  • 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. Please review our Group Size & Multiple Bookings page for guidance.
  • Difficulty: Moderate/Strenuous
  • Length: 8.0 mi
  • Elevation Gain: 3,150 ft
  • 3,900 ft
  • Land Manager: Mount Si NRCA
  • Parking Permit Required: Discover Pass
  • Recommended Party Size: 12
  • Maximum Party Size: 65
  • Maximum Route/Place Capacity: 65
Map
  • Green Trails Mount Si NRCA No. 206S
  • Green Trails Mt Si No. 174
  • USGS Mt Si
Activities

Upcoming Activities

Climbing Conditioner - Mount Si Main Trail

Climbing Clinic
Moderate conditioner for climbers.
Difficulty: Moderate/Strenuous
Sat, Jan 22, 2022
No Prerequisites
0 participants 1 leader
Registration closes Jan 21
Seattle Branch

Field Trip - Baseline Conditioner - Mount Si Main Trail

Climbing Field trip: Basic Alpine Climbing Course
The Baseline Conditioner for the course
Difficulty: Moderate/Strenuous
Sat, Jan 22, 2022
No Prerequisites
1 participant 7 instructors
Registration closes Feb 3
Foothills Branch

Climbing Conditioner - Mount Si Main Trail

Climbing Clinic
Conditioning hike with priority to the SMC-R & Fleming SIGs until Jan 2, open to
Difficulty: Moderate/Strenuous
Sun, Jan 23, 2022
No Prerequisites
0 participants
Registration closes Jan 21
Seattle Branch

TAC MAC Conditioner Series - Mount Si Main Trail

Youth Field trip: Mountaineers Adventure Club - Tacoma
Training hikes and scrambles to get us into shape!
Difficulty: Moderate/Strenuous
Wed, Jan 26, 2022
No Prerequisites
6 participants 0 instructors 1 chaperone
Registration closed Jan 10
Tacoma Branch

Day Hike - Mount Si Main Trail

Day Hiking Trip
Conditioning hike. Priority to the Shafer SIG group.
Difficulty: Moderate/Strenuous
Sat, Jan 29, 2022
No Prerequisites, Leader's Permission Required
3 participants 0 leaders
Registration closed Jan 6
Seattle Branch

Day Hike - Mount Si Main Trail

Climbing Trip
For 2022 Tacoma Basic Alpine students.
Difficulty: Moderate/Strenuous
Sun, Feb 13, 2022
No Prerequisites, Leader's Permission Required
6 participants 2 leaders
Registration opens Jan 24
Tacoma Branch

Climbing Conditioner - Mount Si Main Trail

Climbing Clinic
Bring your heavy pack (35-40 lbs) and assess your fitness level. Everett BCC students/grads only.
Difficulty: Moderate/Strenuous
Sun, Feb 20, 2022
Prerequisites, Leader's Permission Required
4 participants
Registration closes Feb 18
Everett Branch

Conditioning Hike - Mount Si Main Trail

Day Hiking Field trip: Alpine Scrambling Course
Conditioning hike for students in the Tacoma Basic Scrambling Course.
Difficulty: Moderate/Strenuous
Tue, Mar 1, 2022
No Prerequisites
8 participants 0 instructors
Registration closes Feb 27
Tacoma Branch

Conditioning Hike - Mount Si Main Trail

Day Hiking Field trip: Alpine Scrambling Course
Conditioning hike for students in the Tacoma Basic Scrambling Course.
Difficulty: Moderate/Strenuous
Thu, Mar 3, 2022
No Prerequisites
8 participants
Registration closes Mar 2
Tacoma Branch

Conditioning Hike - Mount Si Main Trail

Day Hiking Field trip: Alpine Scrambling Course
Conditioning hike for students in the 2022 Tacoma Alpine Scrambling Course.
Difficulty: Moderate/Strenuous
Sat, Mar 12, 2022
No Prerequisites
7 participants
Registration closes Mar 11
Tacoma Branch

Conditioner Hike - Mount Si Main Trail

Day Hiking Field trip: Basic Climbing Course
Conditioner hike for Tacoma Basic Climbing students
Difficulty: Moderate/Strenuous
Sun, Mar 13, 2022
No Prerequisites
5 participants
Registration closes Mar 11
Tacoma Branch

Climbing Conditioner - Mount Si Main Trail

Climbing Clinic
Race the sun for your conditioner credit. We will leave the main parking lot at
Difficulty: Moderate/Strenuous
Fri, Mar 18, 2022
No Prerequisites
8 participants
Registration closes Mar 16
Seattle Branch

Alpine Scramble - Mount Si Main Trail

Scrambling Trip
Conditioner, This is a SIG activity only, do not ask for permission.
Difficulty: Moderate/Strenuous
Tue, Mar 22, 2022
Prerequisites, Leader's Permission Required
9 participants 0 leaders
Registration closes Mar 20
Seattle Branch

Alpine Scramble - Mount Si Main Trail

Scrambling Trip
Conditioner, This is a SIG activity only, do not ask for permission.
Difficulty: Moderate/Strenuous
Mon, Mar 28, 2022
Prerequisites, Leader's Permission Required
9 participants 0 leaders
Registration closes Mar 26
Seattle Branch

Basic Alpine Climb - Mount Si Main Trail

Day Hiking Trip
Conditioner for Seattle Basic Climbing Dan Fleming SIG
Difficulty: Moderate/Strenuous
Sun, Apr 3, 2022
Prerequisites, Leader's Permission Required
2 participants
Registration closes Apr 1
Seattle Branch

Alpine Conditioner - Mount Si Main Trail

Climbing Clinic
Annual Foothills Mount Si Brunch hike!
Difficulty: Moderate/Strenuous
Sun, Apr 3, 2022
Prerequisites, Leader's Permission Required
9 participants 6 leaders
Registration closes Apr 1
Foothills Branch

Conditioning Hike - Mount Si Main Trail

Day Hiking Field trip: Compressed Alpine Scrambling Course
Conditioning Hike for Seattle Alpine Scrambling Course
Difficulty: Moderate/Strenuous
Thu, Apr 28, 2022
No Prerequisites
10 participants 1 instructor
Registration opens Mar 30; Instructor registration open now
Seattle Branch

Conditioning Hike - Mount Si Main Trail

Day Hiking Field trip: Compressed Alpine Scrambling Course
Conditioning Hike for Seattle Alpine Scrambling Course. Please bring your scrambling pack and a headlamp.
Difficulty: Moderate/Strenuous
Tue, May 3, 2022
No Prerequisites
10 participants 1 instructor
Registration opens Apr 4; Instructor registration open now
Seattle Branch

Basic Glacier Travel - Conditioner Hike - Mount Si Main Trail

Day Hiking Field trip: Basic Glacier Travel Course
After hours Basic Glacier Travel Course conditioner hike. A good opportunity to complete the fitness
Difficulty: Moderate/Strenuous
Tue, May 17, 2022
Prerequisites
9 participants
Registration opens Apr 15
Seattle Branch

Seattle MAC - Conditioning Hike - Mount Si Main Trail

Youth Youth activity: Mountaineers Adventure Club
A conditioning hike to help prepare and train for summer climbing. Interested students are encouraged
Difficulty: Moderate/Strenuous
Sat, May 21, 2022
Prerequisites
0 participants 0 instructors 1 chaperone
Registration closes May 19
Seattle Branch
Carl Marrs
Trip Reports
Titles

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.

  • Mount Si
  • Mount Si via Talus Loop
  • Talus Loop
  • Si, Si Again
  • Double Si
  • Blowdown Mountain
  • Crater Lake Mountain
  • Crater Lake & Blowdown Mountains
  • Dixie Peak
Resources

There are no resources for this route/place. Log in and send us updates, images, or resources.