Mount Si Hiking Guide

Mount Si is the mountain in the opening credits of Twin Peaks and the trail every Washington hiker uses to find out whether they are fit enough for the Cascades. Eight miles round trip, 3,150 feet of gain, and a relentless switchbacking climb through old forest to a boulder field with the Snoqualmie Valley spread out below. Above that sits the Haystack, a rock scramble that a lot of people photograph and rather fewer actually climb.

permit requireddog-friendly
Difficulty
strenuous
Distance
8 mi
Elevation gain
3,150 ft
Trailhead
North Bend
3150-foot climbHaystack summit blockCascade foothillstraining hikeDiscover Pass
springsummerfall

Permit: Discover Pass required to park at the Mount Si trailhead (Mount Si Natural Resources Conservation Area, Washington DNR)

The Benchmark Climb

There is nothing technical about the main trail — it is four miles of steady, unrelenting uphill on good tread, with the grade rarely easing. Seattle hikers use it to condition for Rainier and the alpine lakes, and the standard local question is not whether you have done it but how fast. Three to five hours round trip is typical. The forest cover means views are limited until you reach the top, which some find monotonous and others find meditative.

The Haystack

The true summit requires scrambling the Haystack, a steep rock block above the main viewpoint. It is exposed class 3 and people have died on it. Most hikers stop at the boulder field below, which is where the view is anyway and where everybody eats lunch. If you do go up, treat it as a climb rather than a hike, avoid it when wet or icy, and be honest about your comfort downclimbing steep rock.

Discover Pass and Parking

Mount Si sits in a Washington DNR conservation area and the trailhead requires a Discover Pass — day or annual, bought online or at retailers. Enforcement is routine. The large lot still fills on weekends by early morning despite recent expansion. This is one of the busiest trailheads in the state, and arriving after nine on a summer Saturday usually means a long walk before you start climbing.

Season and Conditions

Hikeable most of the year, which is unusual for a Cascade peak of this size. Snow accumulates on the upper trail from late autumn through spring and microspikes are frequently needed above the halfway point even when the trailhead is bare. Summer is warm and busy; autumn is superb. The forest holds moisture year-round, so expect mud, roots and slick rock regardless of season.

Little Si Alternative

If 3,150 feet is more than you want, Little Si shares the same corner of North Bend at roughly a third of the climb and makes an excellent alternative or warm-up. A lot of local hikers do Little Si while building toward Mount Si, then use Mount Si to build toward genuinely alpine objectives. Leashed dogs are permitted on both, though the Haystack is beyond them.

Hiking tips for Mount Si

  • Buy a Discover Pass before you go — the Mount Si trailhead requires one and enforcement is routine.
  • Treat the boulder field below the Haystack as the summit; the scramble above is exposed class 3 and has killed people.
  • Expect to need microspikes on the upper trail from late autumn through spring, even when the trailhead is clear.
  • Use Little Si as a warm-up if 3,150 feet feels like a stretch — it is the same area at a third of the climb.
  • Arrive before nine on summer weekends; this is one of the busiest trailheads in Washington.

Nearby trails to explore

  • Little Si
  • Rattlesnake Ledge
  • Twin Falls

Hike this trail with TrailMates

Mount Si is the Washington fitness benchmark and a long climb to share. Use TrailMates to find Seattle hikers training for Cascade objectives and starting early at North Bend. Download the TrailMates app to find a partner.