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Seattle Trails

Seattle, WA: Old Mount Si Trail

Try this less-crowded alternative to the top of popular Mount Si on the original, steeper 2.7 mile route.

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In 1987 the Mount Si Conservation Area was expanded and dubbed the Mount Si Natural Resource Conservation Area (NRCA). During that time, the Department of Natural Resources replaced the old trail, and the Washington Trails Association took on caretaking responsibilities of the new trail as its continued to rise in popularity. However, the Old Si Trail, a route that has been guiding hikers to the top of the mountain for over 80 years, is still accessible—and a good way to escape the crowds.

Start at the Little Si trailhead, following the Little Si trail past the first entrance to the Boulder Garden Loop trail. Veer right onto the upper junction with the Boulder Garden trail up past the namesake boulders and mossy outcroppings. At 0.8 mile from the trailhead, be watchful for a rough trail leading upwards—this is the Old Trail. Once on the Old Trail, the path is pretty straightforward—up. This trail is rougher and steeper than the newer incarnation, but there is also much less traffic.

At 2.4 miles, the Old Trail nearly merges with the new trail. Avoid the popular route and veer left, heading back into the trees. A quarter mile farther the trails intersect near the rocky top. Continue the final distance on the newer trail to the top and pick out views of nearby Mailbox Peak, Mt. Washington, and Rattlesnake Ledge. The actual summit, Haystack Rock, lies just ahead, but should only be attempted by experienced climbers. For a change of scenery on the return, complete the Boulder Garden loop trail on the way back down.

Mapped by Nathan & Jeremy Barnes Hiking With My Brother


Trail Facts

  • Distance: 4.4



Location: 47.486794, -121.753406

Park at the trail head for Little Mount Si. If parking lot is full, backtrack down the road 200ft to the parking area by the bridge.


Location: 47.489293, -121.753989

Juntion with the Boulder Garden Loop Trail. Continue straight ahead on the Little Mount Si Trail.


Location: 47.491864, -121.754659

Junction with the exit of the Boulder Garden Loop Trail. Turn right and follow the Boulder Garden Loop trail.


Location: 47.492073, -121.747705

Junction with the Old Si Trail. Continue up and to the left to go to the summit. Turning left finishes the Boulder Garden Loop trail, which is a nice alternate route to take on the way back. The route is slightly longer, but the trail grade is easier.


Location: 47.500296, -121.739711

Junction with the Newer Mount Si Trail. Veer left to continue on the Old Mt. Si trail.


Location: 47.503891, -121.740671

Second Junction with the Newer Mount Si Trail. Turn left and uphill to finish the final portion of the hike on the newer trail.


Location: 47.505155, -121.739861

This viewpoint, named Snoqualmie Point, offers an excellent vantage point of the valley.


Location: 47.506878, -121.738966

For the experienced scrambler, the actual summit can be attained by climbing up the Haystack. Use extreme caution, as many have fallen fatally from the route to the top.

Trail Sign

Location: 47.489354, -121.753814

Boulder Garden

Location: 47.492573, -121.749641

Winding Switchbacks

Location: 47.499083, -121.742141

Rattlesnake Mountain

Location: 47.504591, -121.739695

First Prominence

Location: 47.504765, -121.739609


Location: 47.505258, -121.739674

Robber Jay

Location: 47.505142, -121.739513


Location: 47.506302, -121.739448

The Haystack—the actual summit of Mount Si, covered in a shroud of morning fog.

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