Fair Oaks is a census-designated place (CDP) in Sacramento County, California, United States. It is part of the Sacramento–Arden-Arcade–Roseville Metropolitan Statistical Area. The population was 30,912 at the 2010 census, up from 28,008 at the 2000 census. Fair Oaks's zip code is 95628 and its area code is 916. Fair Oaks is bounded on the south side by the American River, and Rancho Cordova, on the north side by the city of Citrus Heights, on the west side by Carmichael, and the east side by Orangevale.