The Orange County Marathon is an annual 26.2-mile (42.2 km) marathon that takes place in Orange County, California. The primary marathon was held in 1979, and it has been held yearly since then. The marathon is often held in late October or early November.
The Orange County Marathon is among the largest marathons in the US, with over 20,000 contributors in 2019. The marathon can be a Boston Marathon qualifier, that means that runners who end the Orange County Marathon with a qualifying time can routinely qualify for the Boston Marathon.