updated 9/20/2021
NOTICE: The 2021 Trailhead Direct Service will not be running to Mailbox Peak, but it does serve nearby Destinations.
Ten years ago, Mailbox Peak was a little known route used a by a few peak-baggers. Then the trail was discovered by athletes drawn by the 4000' of elevation gain. Word about the hike spread on various social media, and the number of hikers exploded seemingly overnight. The fact that the trail was steep and tough became an attraction, not a deterrent, for many. Reaching the summit became the perfect Facebook/Instagram/Strava moment. Don't expect to be alone on weekends.
With the increasing usage, the Department of Natural Resources, the land manager for the area decided that new, better-constructed trail was needed. Completed a few years ago, this new trail takes 5 miles to reach the peak. The old steep route, which gains the 4000' in less than three miles, remains popular with the fitness crowd. Either trail involves a long ascent in a thick, view-less second growth forest. It can be a dull as well as tiring experience. The old and new trails eventually rejoin high on the peak, and the final climb up the windswept and bare ridge offers grand views. Atop the peak you will find the eponymous mailbox stuffed full of all sorts of odd things. Try to find a spot amidst the crowd of happy hikers, and enjoy the scenery.
Ride Sound Transit 554 from Seattle to Issaquah Transit Center, then hop aboard the weekend-only Mailbox Peak shuttle run by Trailhead Direct.
The bus drops you off at the lower parking lot at the Mailbox Peak Trailhead. Hike up the driveway to the upper parking lot, then continue walking on a gravel logging road. The new Mailbox Peak trail starts on the left a short distance up the road. If you want to go on the old, steep trail, continue walking up the gravel logging road another quarter mile.
The new trail climbs the peak in long, moderately -graded switchbacks. It is a bit of a dull climb in thick forest, at least until you reach 3000' where views open up in rocky areas. At 3800' the new trail joins the old one. Congratulations, you still have a thousand feet to go! Now the scenery becomes spectacular as the trees thin out. You will need all the motivation you can get to ascend this last portion of the trail, much of which is little improved and climbs steeply up the fall line.
The 4800' summit of Mailbox Peak offers an unobstructed view in every direction, as well as the famous mailbox. There is good cell service, so be sure to upload that selfie to Facebook!
The old trail is the tough alternative route to the peak. The grade is relentlessly steep and your calf muscles will feel the burn. The round-trip distance to the peak is only 5.4 miles using this route, but your knees are going to hate you on the way down. Getting passed by super-athletes running up this trail (they get to the peak in an hour) will make you feel even more old and tired.