Stewart, OhioStewart is an unincorporated community and census-designated place in central Rome Township, Athens County, Ohio, United States. The population was 221 at the 2020 census. It has a post office with the ZIP code 45778.HistoryStewart was laid out in 1875, when the railroad was extended to that point. The community was named for Daniel Bertine Stewart, the original owner of the town site. A post office has been in operation at Stewart since 1874.GeographyStewart is located along the Hocking River, just upstream from the confluence of Federal Creek with the river. It is located at the intersection of State Routes 144 and 329.