Get ready for a spooktacular day of fun and fitness at the Issaquah Schools Foundation Monster Mash 5K on Saturday, October 25th, 2025! This exciting community event, located in Issaquah, King County, invites participants of all ages and abilities to join in the festivities while raising funds to support local students across all 27 Issaquah School District schools.

Whether you're aiming to set a personal record or enjoy a leisurely stroll with family and friends, the professionally chip-timed course features a flat, paved out-and-back route that ensures a fantastic experience for everyone. Don your most creative and festive costumes to add to the Halloween spirit! With convenient onsite parking, phased start times, and plenty of fun perks including a 2025 Monster Mash technical race tee and medal for early registrants, this event is not to be missed. Plus, you'll receive free event photos and raffle tickets for exciting prizes! Join us for a morning of camaraderie, competition, and community spirit—register early as this popular event sells out every year!