Highest peak
Mailbox Peak
4,845 ft / 1,476 m
Most prominent peak
Rattlesnake Mountain East Peak
2,520 ft / 768 m prom
Most climbed peak
Mount Si
365 climbs
Most difficult peak
Mailbox Peak
Class 1
Difficulty breakdown
Class 1/2 2 peaks
Class 3/4 1 peak
Highlights
Latest climbs
"I've done this before but never in the winter. I love these peaks along the I-90 corridor since they are so accessible for those of us that live in Seattle. This is one of the better winter hikes I've done if you're looking for something closer to a traditional hike (no snowshoes or thick snow w/postholing) granted we have had minimal snow this year. Snow on trail at 3800 ft+ but didn't even take my spikes out. Fresh dusting of snow on the trees surrounding Change Peak was beautiful." — E • Feb 10, 2026
"July 4 🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸🇺🇸
Trail run up Little Si in the morning, good view of Mount Si and post-peak bakery run at The North Bend Bakery. Definitely go there! (oreo milkshakes looked delicious)
🦅🦅🦅🦅🦅🦅🦅🦅" — summit • Jul 4, 2025
"Some sections past the Ira Springs connector were pretty overgrown. Also, getting to Dirtybox from DHP would have involved climbing down about 15 ft or so on a rope, so I decided not to. I'll try Dirtybox from the Mailbox side instead." — mathiasricken • Jul 21, 2024
"Some sections past the Ira Springs connector were pretty overgrown. Also, getting to Dirtybox from DHP would have involved climbing down about 15 ft or so on a rope, so I decided not to. I'll try Dirtybox from the Mailbox side instead." — mathiasricken • Jul 21, 2024
"Decided we wanted some off-trail fun close to home and boy did we get that. AK and I started at the lower Tinkham Road trailhead @ 7 am and found our way back there about 10 hours later. We created a loop which had us on top of 6 different peaks, a single day PR for me (in order): Dirty Harry's Balcony, Dirty Harry's Peak, Coincidence Point, Webb Mountain, P3, Defiance. It was extremely slow going between Dirty Harry's Peak and Webb Mountain -- maximum bushwhacking and negotiating the endless boulders on that thing was exhausting. My favorite part was probably the traverse between Webb and Defiance. " — zachmitch • Jun 29, 2024
