Haydenville is an unincorporated community in southern Green Township, Hocking County, Ohio, United States. It lies along U.S. Route 33 and the Hocking River, southeast of the city of Logan, the county seat of Hocking County. Its elevation is 705 feet (215 m), and it is located at 39°28′55″N 82°19′42″W / 39.48194°N 82.32833°W / 39.48194; -82.32833 (39.4820130, -82.3282074). Although Haydenville is unincorporated, it has a post office, established on January 10, 1870, and a nearby cemetery. Its ZIP code is 43127; the ZCTA for ZIP Code 43127 had a population of 67 at the 2000 census. In 1973, the community was listed on the National Register of Historic Places as a historic district under the name of "Haydenville Historic Town. " Over 120 contributing properties were included in the historic district's 20 acres (8.1 ha).