There are 4 US Post Offices in Madison County serving a total of 19,844 residents equating to 4,961 residents per post office. It's estimated that approximately 31,673 packages are handled across the 4 county post offices annually. Madison County is a county located in the state of Florida. As of the 2010 census, the population was 19,224. Its county seat is Madison. Madison became a wet county as of August 28, 2012, meaning that the sale, possession, or distribution of alcoholic beverages is legal."