Foothill Ranch is a neighborhood of the city of Lake Forest in Orange County, California, United States. The population was 10,899 at the 2000 census. The master planned community was a census-designated place prior to being incorporated into the city in 2000. Foothill Ranch is notable for being the headquarters of Oakley, Inc., and ProBoards. Other companies such as Nike, Kaiser Aluminum, Kawasaki, and TAE Technologies also have offices in Foothill Ranch.