There are 11 US Post Offices in Trempealeau County serving a total of 29,849 residents equating to 2,714 residents per post office. It's estimated that approximately 47,642 packages are handled across the 11 county post offices annually. Trempealeau County is a county located in the U.S. state of Wisconsin. As of the 2010 census, the population was 28,816. Its county seat is Whitehall."