There are 3 US Post Offices in Beaver County serving a total of 6,466 residents equating to 2,155 residents per post office. It's estimated that approximately 10,320 packages are handled across the 3 county post offices annually. Beaver County is a county located in the U.S. state of Utah. As of the 2010 census, the population was 6,629. Its county seat and largest city is Beaver. The county was named for the abundance of beavers in the area."