There are 7 US Post Offices in Dixon County serving a total of 6,028 residents equating to 861 residents per post office. It's estimated that approximately 9,621 packages are handled across the 7 county post offices annually. Dixon County is a county in the U.S. state of Nebraska. As of the 2010 census, the population was 6,000. Its county seat is Ponca. The county was created in 1856 and attached to Dakota County. It was organized in 1858. Dixon County is part of the Sioux City, IA\u2013NE\u2013SD Metropolitan Statistical Area. In the Nebraska license plate system, Dixon County is represented by the prefix 35 (it had the 35th-largest number of vehicles registered in the county when the license plate system was established in 1922)."