There are 4 US Post Offices in Pawnee County serving a total of 2,333 residents equating to 583 residents per post office. It's estimated that approximately 3,724 packages are handled across the 4 county post offices annually. Pawnee County is a county in the U.S. state of Nebraska. As of the 2010 census, the population was 2,773. Its county seat is Pawnee City. In the Nebraska license plate system, Pawnee County is represented by the prefix 54 (it had the fifty-fourth-largest number of vehicles registered in the county when the license plate system was established in 1922)."