You can hike 2.3 miles straight through a Washington mountain, but the tunnel closes November 1
You can walk straight through the inside of a mountain in Washington, and the window to do it closes November 1. The Snoqualmie Tunnel runs 2.3 miles under the Cascades near Snoqualmie Pass, with no summit, no switchbacks, and no views until you pop out the far end.
It’s one of the stranger hikes in the state, and honestly one of the best ones to do on a rainy October day. The trail is part of the Palouse to Cascades State Park Trail, and the tunnel sits right where the West and Central sections meet.
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A railroad tunnel that outlived its trains
The Milwaukee Road railroad dug this tunnel between 1912 and 1914 as part of its line from Chicago to Seattle. The last train rolled through on March 15, 1980, and the tracks were eventually pulled out. Now it’s a flat, crushed-rock path for walkers and bikes.
Picture a perfectly straight, pitch-black corridor with a tiny dot of daylight at the far end. That dot takes a very long time to get bigger!
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The numbers
From the Iron Horse State Park trailhead off I-90 Exit 54, the out-and-back walk to the far end and back is about 5.3 miles with no real climbing. Easy on the legs, but 5 miles in the dark has its own way of wearing you down.
The tunnel stays cool and damp even on hot days, so bring a real jacket. A headlamp or flashlight is non-negotiable, and my strong opinion is to carry a spare light and batteries instead of trusting your phone. It’s also smart to wear something reflective or clip on a blinking light, because bikes come up on you quickly.
Parking and getting there
The tunnel sits on state park land, so you’ll need a Discover Pass for your car; Washington State Parks lists a one-day pass at $10 and an annual pass at $45. From Seattle, take I-90 east to Exit 54 and follow the signs for Iron Horse State Park.
Already out on the pass? The Franklin Falls hike is a short drive away and makes a solid second stop for the day.
Don’t wait on this one
The tunnel is closed November 1 through May 1 each year, and State Parks notes the reopening date depends on the weather. Check the official State Parks trail page for current alerts before you head out.
Have you ever walked through a mountain? Tell us in the comments if you’ve done this one, and what you wished you had brought with you.
Trip tips: grab a rental car to get out here, lock in your hotel before the good rooms are gone, or skip both and book a camper van instead.
Rules and fees change — always confirm current requirements before you go.
