There are 9 US Post Offices in Cedar County serving a total of 8,685 residents equating to 965 residents per post office. It's estimated that approximately 13,862 packages are handled across the 9 county post offices annually. Cedar County is a county in the U.S. state of Nebraska. As of the 2010 census, the population was 8,852. Its county seat is Hartington. The county was formed in 1857 and named for the many cedars that grow there. In the Nebraska license plate system, Cedar County is represented by the prefix 13 (it had the 13th-largest number of vehicles registered in the county when the license plate system was established in 1922)."