There are 15 US Post Offices in Jasper County serving a total of 97,048 residents equating to 6,470 residents per post office. It's estimated that approximately 154,899 packages are handled across the 15 county post offices annually. Jasper County is a county located in the southwest portion of the U.S. state of Missouri. As of the 2010 census, the population was 117,404. Its county seat is Carthage, and its largest city is Joplin. The county was organized in 1841 and named for William Jasper, a hero of the American Revolutionary War. Jasper County is included in the Joplin, MO Metropolitan Statistical Area. The Jasper County Sheriffs office has jurisdiction throughout the county."