There are 10 US Post Offices in Ross County serving a total of 134,293 residents equating to 13,429 residents per post office. It's estimated that approximately 214,347 packages are handled across the 10 county post offices annually. Ross County is a county located in the Appalachian region of the U.S. state of Ohio. As of the 2010 census, the population was 78,064. Its county seat is Chillicothe, the first and third capital of Ohio. Established on August 20, 1798, the county is named for Federalist Senator James Ross of Pennsylvania. Ross County comprises the Chillicothe, OH Micropolitan Statistical Area, which is also included in the Columbus-Marion-Zanesville, OH Combined Statistical Area."