Cougar Mountain Trail Run Series

Embark on an unforgettable trail adventure at the Cougar Mountain Trail Run Series on July 11, 2026, nestled in the heart of Bellevue, WA. This esteemed event, part of a long-running series, invites runners to explore the diverse and captivating Cougar Mountain Regional Wildland Park, an integral part of the "Issaquah Alps." Choose your challenge from three distances: a demanding 19.5-mile course, a robust 10.8-mile option, or a swift 5K. The courses weave through a lush forest of fern-lined single-track trails, offering a mix of rolling hills, moderate climbs, and short, steep inclines, alongside scenic marshes and wetland habitats. While panoramic views are scarce, the beauty of the dense woodland provides a continuously engaging backdrop, with trails ranging from technical, root-and-rock-laden sections to wider, more groomed paths.

Known for its excellent organization by the Seattle Running Club and Northwest Trail Runs, this series has a strong reputation for well-marked trails and a welcoming community atmosphere, making it a popular training ground for local trail enthusiasts. Runners appreciate the post-race camaraderie, complete with food and beverages. Aid stations along the course are well-stocked, though participants are asked to bring their own refillable water containers as part of the event's "cup-free" initiative, promoting a greener race experience. Typical race day conditions in July are ideal for trail running, with highs around 76°F and lows around 56°F, and only a 2% chance of precipitation.

The Cougar Mountain Trail Run Series stands out for its commitment to the local environment, having donated over $265,000 to King County Parks, directly supporting the maintenance of these cherished wildlands. Starting and finishing at the Sky Country Trailhead off 166th Way SE, the event provides a convenient yet immersive escape into nature. Whether you're aiming for a personal best, building endurance for a fall ultra, or simply seeking a beautiful run in a supportive environment, the Cougar Mountain Trail Run Series offers an exceptional trail running experience for all skill levels.