Three Days in the Park is a multi-day fun run held in Sandy Hills Regional Forest in Elmira, Ontario. Participants can choose from 72-hour, 48-hour, or 24-hour options. The event begins at 9 a.m. on a Thursday and concludes at 9 a.m. on a Sunday, utilizing staggered starts to ensure all participants finish within the same time frame. Founder Clay Williams established the run after completing a 200-mile run, aiming to share the satisfaction of completing a challenging endeavor with others.
The event's format is straightforward yet demanding. Each option involves a one-mile loop featuring a short, steep hill, requiring runners to traverse the same section of forest repeatedly as the hours progress. Williams intentionally presents it as a fun run, prioritizing personal achievements and support for the Mood Disorders Society of Canada over competitive rankings or awards.