California is a home rule-class city in Campbell County, Kentucky, United States. The population was 90 at the 2010 census.
California, Kentucky was founded ca. 1849, and named from news reports of the contemporaneous California Gold Rush. A post office has been in operation at California since 1852. California was incorporated as a city on February 7, 1874.
The Elijah Herndon House in California is listed on the National Register of Historic Places in Campbell County.
California is located in southeastern Campbell County at 38°55′9″N 84°15′48″W (38.919144, −84.263381), along the Ohio River. Kentucky Route 8 passes just west of the community, leading northwest (downstream) along the river 23 miles (37 km) to Covington and southeast (upstream) 21 miles (34 km) to Augusta. Clermontville, in Clermont County, Ohio, is directly across the river from California, but the closest bridge across the river is Interstate 275 14 miles (23 km) downriver.
According to the United States Census Bureau, the city of California has a total area of 0.25 square miles (0.66 km2), all land.
The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, California has a humid subtropical climate, abbreviated "Cfa" on climate maps.
As of the census of 2000, there were 86 people, 26 households, and 21 families residing in the city.