Foothill Ranch (FHR) 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 such company headquarters as Oakley, Inc., Wet Seal, Emergen-C, Kaiser Aluminum, Tri Alpha Energy, Inc., and ProBoards. It is also the home of Saddleback Church.