Mailbox Peak

A strenuous day hike with 4,100 feet of elevation gain. The original path heads straight up the ridge through the forest to the rocky summit for a 6-miles round trip. The new trail switchbacks to the summit for 11.2 miles round trip.

getting there

Take Exit 34 off of I-90 and drive north on 468th Ave SE for ~0.5 mile. Turn right onto SE Middle Fork Road, continue for 2.5 miles, turn right and drive ~200 yards to the Mailbox Peak trailhead (900 ft).


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


11.2 miles round trip with 4,100 feet of elevation gain

In response to a continued increase in usage, the Mountains to Sound Greenway and the Washington State Department of Natural Resources opened a new, more sustainable trail up Mailbox Peak in the Middle Fork Snoqualmie River Valley in 2014. This new 5-mile trail has offered increased access to this already popular area. Volunteers play a crucial role in keeping this already well-loved trail maintained.


6 miles round trip with 4,100 feet of elevation gain

The original route up Mailbox Peak heads straight up the ridge through the forest to the rocky summit.

dirtybox peak (4,926 ft)

8.5 miles with 4,570 feet of elevation gain

Dirtybox Peak lies on the ridge between Mailbox Peak and Dirty Harry's Peak.  Follow the old Mailbox Peak path to the summit of Mailbox Peak, then continue down and across the Southeast Ridge to Dirtybox Peak.  


Scheduling & Permits

  • 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.
  • 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 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.
  • Difficulty: Very Strenuous, Snow Scramble, Winter Scramble
  • Length: 11.2 mi
  • Elevation Gain: 4,100 ft
  • 4,841 ft
  • Land Manager: Middle Fork NRCA
  • Parking Permit Required: Discover Pass
  • Recommended Party Size: 12
  • Maximum Party Size: 20
  • Maximum Route/Place Capacity: 20
  • Green Trails Mount Si NRCA No. 206S
  • Green Trails Middle Fork Snoqualmie No. 174SX
  • Green Trails Bandera No. 206
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.

  • Dirtybox Peak
  • Mailbox & Dirtybox Peaks

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