According to the County of Hunterdon's website, Califon was a station on the High Bridge Railroad, and was relatively quiet until the mid-1800's. The rather odd name, "Califon" is shortened from the original one: California. Some local legends have it that it was shortened because the mailing address of "California, New Jersey" was confusing the postal system, as it was at the time. Others have it that the name was too long for the train depot sign, and it was summarily chopped to fit! It's unlikely that either is the actual reason, but at any rate, Califon has been Califon ever since. Long after the name-game was over, the Borough of Califon was formed in the early 1900's.

Over 150 structures in Califon are registered with the National Register of Historic Places, thanks to the hard work of the Califon Historical Society. The tan wood plaques visible on Califon buildings are the mark of the National Register.