12 Hours of Lawrence Woods

The 12 Hours of Lawrence Woods is a half-day ultrarunning event held in Medford, Massachusetts, within the scenic Lawrence Woods section of the Middlesex Fells Reservation. Participants run a roughly 5-mile loop course that stays within the woods without crossing over itself, sharing only one intersection with opposing turns. The event features a minimal aid station offering water, candy, and sugary drinks, encouraging runners to bring their own gear and set up personal spots along the course.

The start, finish, and aid station are located about a quarter mile from the nearby high school parking lot. The atmosphere is casual and community-oriented, welcoming runners and volunteers alike. Visit the organization's website for the most recent information.