 San Juan Creek, also called the San Juan River, is a 29-mile (47 km) stream in Orange County, California that consists of a catchment basin encompassing 133.9 square miles (347 km2). Its mainstem rises in the Santa Ana Mountains, in the Trabuco Ranger District of the Cleveland National Forest. From there it runs parallel to the Ortega Highway as it winds west and south through San Juan Canyon, where it is joined by numerous small tributaries, and is joined by Trabuco Creek, its main branch as it passes through San Juan Capistrano. It flows into the Pacific Ocean at Doheny State Beach. Once out of the foothills, San Juan Creek flows through the city of San Juan Capistrano where groundwater flow direction generally is from the northeast to the southwest. Groundwater in this basin at the San Juan Capistrano reach is considered good. Recent efforts of stream conservation have been in the planning stage including habitat conservation plan work.
