Julian is a census-designated place (CDP) in San Diego County, California, in the United States. As of the 2010 census, the population was 1,502, down from 1,621 at the 2000 census. Julian is an official California Historical Landmark No. 412. Also, the Julian townsite and surrounding area is defined by the San Diego County Zoning Ordinance Section 5749 as the Julian Historic District.