There are 6 US Post Offices in Jefferson County serving a total of 7,447 residents equating to 1,241 residents per post office. It's estimated that approximately 11,886 packages are handled across the 6 county post offices annually. Jefferson County is a county located in the U.S. state of Nebraska. As of the 2010 census, the population was 7,547. Its county seat is Fairbury. The county was named in honor of Thomas Jefferson, third President of the United States of America. In the Nebraska license plate system, Jefferson County is represented by the prefix 33 (it had the thirty-third-largest number of vehicles registered in the county when the license plate system was established in 1922)."