St. Johns is an unincorporated community in northwest St. Johns County, Florida, United States and a suburb of Jacksonville. The population as of the 2000 census was 18,063, though considerable growth has taken place in the past ten years. As of 2016, the population is estimated to be approximately 86,400 people. It is located in the Jacksonville metropolitan area, and lies approximately halfway between downtown Jacksonville and downtown St. Augustine.
St. Johns is made up of the entire 32259 ZIP code, including the communities of Fruit Cove, Switzerland and Julington Creek. This ZIP code claimed a population of 36,917 at the 2010 census, for a land area of 57.66 square miles.