There are 4 US Post Offices in Phelps County serving a total of 8,888 residents equating to 2,222 residents per post office. It's estimated that approximately 14,186 packages are handled across the 4 county post offices annually. Phelps County is a county in the U.S. state of Nebraska. As of the 2010 census, the population was 9,188. Its county seat is Holdrege. The county was formed in 1873 and named after William Phelps, an early settler in the area. In the Nebraska license plate system, Phelps County is represented by the prefix 37 (it had the thirty-seventh-largest number of vehicles registered in the county when the license plate system was established in 1922). It is considered part of the Kearney \u03bcSA's development and expansion plans."