There are 18 US Post Offices in Cayuga County serving a total of 75,790 residents equating to 4,211 residents per post office. It's estimated that approximately 120,969 packages are handled across the 18 county post offices annually. Cayuga County is a county located in the U.S. state of New York. As of the 2010 census, the population was 80,026. Its county seat is Auburn. The county was named for one of the tribes of Indians in the Iroquois Confederation. Cayuga County comprises the Auburn, NY Micropolitan Statistical Area, which is also included in the Syracuse-Auburn, NY Combined Statistical Area."