Califon is a borough in Hunterdon County, in the U.S. state of New Jersey. As of the 2020 United States census, the borough's population was 1,005, a decrease of 71 from the 2010 census count of 1,076, which in turn reflected an increase of 21 from the 1,055 counted in the 2000 census. The borough's name is said to have been inspired by the California gold rush of 1849. The name was shortened to Califon, supposedly because the longer name could not be fit on signs at the train station.