Welcome to the 2026 edition of the Cougar Mountain Trail Series. This year is the 22nd running of this event. The series is put on by Seattle Running Club and Northwest Trail Runs and supports King County Parks. Since the beginning of the series, we have donated over $240,000 to King County Parks.

The October 31st Race will have a handful of distances: 5K, 7.6 miles, 19.5 miles, and the 50K.