There are 22 US Post Offices in Greene County serving a total of 36,827 residents equating to 1,674 residents per post office. It's estimated that approximately 58,780 packages are handled across the 22 county post offices annually. Greene County is a county located in the U.S. state of Pennsylvania. As of the 2010 census, the population was 38,686. Its county seat is Waynesburg. Greene County was created on February 9, 1796, from part of Washington County and named for General Nathanael Greene. Greene County is part of the Pittsburgh DMA. It is located in the area of southwestern Pennsylvania that was formerly claimed by Virginia, the District of West Augusta."