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Glacial Erratics: Awesome Giant Rocks to Visit Around Seattle

Huge rocks carried by glaciers are fascinating and fun to climb on

Annie Fanning

Published on: October 21, 2021

Glacial Erratics: Awesome Giant Rocks to Visit Around Seattle

Cougar Mountain’s Fantastic Erratic
Cougar Mountain’s glacial erratic

Cougar Mountain’s Fantastic Erratic, Issaquah

Wearing a gorgeous shag of licorice fern, the Fantastic Erratic watches over the Talus Open Space, adjacent to Cougar Mountain Regional Wildland Park in Issaquah.

For a quick visit to this majestic wonder, park at the Bear Ridge Trailhead off SR 900 and take the Bear Ridge Trail uphill about a mile. (For a longer hike, you can come down from the Shangri La Trail. Check out the park’s trail map for alternate routes.)

Deposited on this hillside by a northern glacier, this erratic is metamorphic, created under the Earth’s surface by intense pressure and heat. In some of its jagged cracks you might notice orange staining, which is from iron-rich water percolating through the rock. The ferns must lust for rust because they are really digging into this erratic!

Getting there: From Interstate 90, take exit 15 and drive south on 17th Avenue Northwest, which becomes Renton-Issaquah Road Southeast, also called SR 900. Just past Talus Entrance Road, look for the small parking area at the Bear Ridge trailhead. Note that Bear Ridge Trail connects with King County’s Cougar Mountain Regional Wildland Park trail system.

Follow the trail uphill for about a mile. It may seem longer, but it is not. Bring chocolate.

If you go: Drive back through Issaquah if you’ve worked up an appetite. Pick up kid-friendly Indian takeout at popular Bukhara (131 Front St. N.). For lighter fare or hot chocolate, try Issaquah Coffee Company (317 N.W. Gilman, No. 47).

Editor's note: This article was originally published a few years ago, but the big rocks haven't changed a bit since then.

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