There are 1 US Post Offices in Mcpherson County serving a total of 441 residents equating to 441 residents per post office. It's estimated that approximately 704 packages are handled across the 1 county post offices annually. McPherson County is a county located in the U.S. state of Nebraska. As of the 2010 census, the population was 539, making it the third-least populous county in Nebraska and the eighth-least populous county in the United States. Its county seat is Tryon. The county was formed in 1890 from Logan County and named after Union General James B. McPherson. McPherson County is part of the North Platte, NE Micropolitan Statistical Area. In the Nebraska license plate system, McPherson County is represented by the prefix 90 (it ranked 90th of 93 counties in the number of vehicles registered when the license plate system was established in 1922)."