California International Marathon

California International Marathon takes place in Folsom, California, on December 5–6, 2026, organized by the Sacramento Running Association. The main event, the marathon (26.2 miles), starts at 7:00 a.m. on Sunday, December 6, alongside a Marathon Relay over the same distance. On Saturday, December 5, a mara FUN run 5K opens the weekend. Known as CIM, the race is a point-to-point course with a net downhill profile that runs from Folsom Dam to the California State Capitol in Sacramento, dropping roughly 300 feet along the way.

This is a certified road marathon with a reputation as one of the fastest in the country, often called the fastest road to Boston. It draws runners chasing a Boston Qualifier, an Olympic Trials standard, or simply a marathon PR, and with around 10,000 participants it ranks among the ten largest marathons in the United States. If you are targeting a fast time here, plan a 16- to 18-week build with a weekly long run and a few sessions that practice sustained downhill running, so your quads are ready for the descent. The relay lets a team share the same course, and the Saturday 5K works as a shakeout or a family option.