There are 6 US Post Offices in Marquette County serving a total of 14,396 residents equating to 2,399 residents per post office. It's estimated that approximately 22,978 packages are handled across the 6 county post offices annually. Marquette County is a county located in the U.S. state of Wisconsin. As of the 2010 census, the population was 15,404. Its county seat is Montello. The county was created in 1836 from the Wisconsin Territory and organized in 1848."