Home Events & Festivals Mill Race Marathon Twitter Facebook Print About Mill Race MarathonBegins downtown. A full marathon, a half-marathon, and a 5K. Sanctioned by United States of America Track and Field (USATF) and a certified Boston Marathon qualification course. Other events include Mill Race Expo on Friday night at The Commons, the Kid’s Fun Run at Mill Race Park on Friday evening, and the “Finish on Fourth” post-race celebration on Saturday afternoon and evening. Powered by Cummins.