Cougar Mountain Trail Run Series

Event overview

The Cougar Mountain Trail Run Series (May) takes place on May 9, 2026 at Sky Country Trailhead in Bellevue, Washington. The series is organized by Seattle Running Club and Northwest Trail Runs and supports King County Parks, with $15 from each entry donated to the parks. The event is held in Cougar Mountain Regional Wildland Park, about 15 minutes from Seattle, on fern-lined single-track trails that pass through marshes and wetland habitat. The course features rolling hills, a few moderate climbs, and a few short steep inclines. The series has raised over $265,000 for King County Parks.

Races, registration, and policies

Distances offered for the May event:

• 5.1 miles
• 10.8 miles

The event also offers series passes: the Short Series (May 5.1, June 8.2, July 10.8, August 14.5) and the Long Series (May 10.8, June 14.5, July 19.5, August 26.2). Registration opens February 10, 2026 and online registration for each event closes the Wednesday before that event; day-of registration is available. Published entry fees for May: 5.1 miles $50 plus processing fee, 10.8 miles $60 plus processing fee; short series and long series pass prices are listed on the event page. There is a participant cap, no refunds, and series awards use the best 3 out of 4 races for eligibility. Top 3 Men, Women, and Nonbinary runners in each event receive podium prizes; top overall Men, Women, and Nonbinary based on cumulative time receive awards and a free entry into the next year’s series. Dogs are not allowed on the course. The series is cup-free and requests runners bring refillable water containers for aid stations. Photo consent and event safety guidelines are part of event policies. Visit the organization's website for the most recent information.