There are 10 US Post Offices in Pierce County serving a total of 47,790 residents equating to 4,779 residents per post office. It's estimated that approximately 76,278 packages are handled across the 10 county post offices annually. Pierce County is a county located in the U.S. state of Wisconsin. As of the 2010 census, the population was 41,019. Its county seat is Ellsworth. Pierce County is part of the Minneapolis\u2013St. Paul\u2013Bloomington, MN-WI Metropolitan Statistical Area."