There are 15 US Post Offices in Greene County serving a total of 132,869 residents equating to 8,858 residents per post office. It's estimated that approximately 212,074 packages are handled across the 15 county post offices annually. Greene County is a county located in the U.S. state of Ohio. As of the 2010 census, the population was 161,573. Its county seat is Xenia. The county was established on March 24, 1803 and named for General Nathanael Greene, an officer in the Revolutionary War. Greene County is part of the Dayton, OH Metropolitan Statistical Area."