Foothill Ranch was a census-designated place in Orange County, California, United States. The population was 10,899 at the 2000 census. Foothill Ranch was incorporated into Lake Forest, California, in 2000.Foothill Ranch is notable for companies such as Oakley, Inc., COX Communications, Nike, Kaiser Aluminum, Kawasaki, Hampton Products/Brinks, Tri Alpha Energy, Viking Technology, Image Options and ProBoards. It is also the home of Saddleback Church.