Fallbrook is an unincorporated community in northern San Diego County, California. The Fallbrook census-designated place (CDP) population was 30,534 at the 2010 census, up from 29,100 at the 2000 census. Fallbrook's downtown is not on any major highway route. It is 6 miles (9.7 km) west of Interstate 15 or 5 miles (8.0 km) north of State Route 76. Fallbrook is situated immediately east of the U.S. Marine Corps' Camp Pendleton.