Join Seattle Running Club and Northwest Trail Runs for the 2026 Cougar Mountain Trail Run Series, a fantastic way to support King County Parks with $15 from each entry fee going directly to the cause. The August 8 event features three distance options—a 5K, 14.5 miles, and a full marathon—with staggered start times (8:30 AM for the longer distances, 9 AM for the 5K) and a 4 PM cutoff time. This scenic trail running series takes place throughout the year at Cougar Mountain in Bellevue, WA, offering runners of various abilities the chance to tackle different distances while giving back to the community.