Dixon County is a county in the U.S. state of Nebraska. As of the 2020 United States Census, the population was 5,606. 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–NE–SD Metropolitan Statistical Area. In the Nebraska license plate system, Dixon County is represented by the prefix 35.