Fair Oaks is a census-designated place in Sacramento County, California, United States. It is part of the Sacramento–Arden-Arcade–Roseville Metropolitan Statistical Area. The population was 32,514 at the 2020 census, up from 30,912 at the 2010 census. The Fair Oaks zip code is 95628 and its area codes are 916 and 279. It is bordered to the west by Carmichael, north by the city of Citrus Heights, to the east by Orangevale, and to the south by the American River.