There are 15 US Post Offices in Greene County serving a total of 249,050 residents equating to 16,603 residents per post office. It's estimated that approximately 397,512 packages are handled across the 15 county post offices annually. Greene County is a county located in the U.S. state of Missouri. As of the 2010 census, the population was 275,174, making it the fourth-most populous county in Missouri. Its county seat is Springfield. The county was organized in 1833 and is named after American Revolutionary War General Nathanael Greene. Greene County is included in the Springfield, MO Metropolitan Statistical Area."