There are 10 US Post Offices in Marquette County serving a total of 66,345 residents equating to 6,635 residents per post office. It's estimated that approximately 105,894 packages are handled across the 10 county post offices annually. Marquette County is a county located in the Upper Peninsula of the US state of Michigan. As of the 2010 census, the population was 67,077. The county seat is Marquette. The county is named for Father Marquette, a Jesuit missionary. It was set off in 1843 and organized in 1851. Marquette County is the largest county in land area in Michigan, and the most populous county in the Upper Peninsula of Michigan. Marquette County comprises the Marquette, MI Micropolitan Statistical Area."