There are 22 US Post Offices in Ontario County serving a total of 109,548 residents equating to 4,979 residents per post office. It's estimated that approximately 174,851 packages are handled across the 22 county post offices annually. Ontario County is a county located in the U.S. state of New York. As of the 2010 census, the population was 107,931. The county seat is Canandaigua. Ontario County is part of the Rochester, NY Metropolitan Statistical Area. In 2006, Progressive Farmer rated Ontario County as the \"Best Place to Live\" in the U.S., for its \"great schools, low crime, excellent health care\" and its proximity to Rochester."