| Williamstown, Ohio | |
| Nickname: | Billtown |
| Coordinates: | 40.8339°N -83.6508°W |
| Subdivision Type: | Country |
| Subdivision Name: |  United States |
| Subdivision Type1: | U.S. state |
| Subdivision Name1: | Ohio |
| Subdivision Type2: | County |
| Subdivision Name2: | Hancock County |
| Subdivision Type3: | Township |
| Subdivision Name3: | Madison Township |
| Established Date: | 1834 |
| Founder: | John W. Williams |
| Unit Pref: | US |
| Population Density Sq Mi: | auto |
Williamstown is an unincorporated community in southern Madison Township, Hancock County, Ohio, United States. Although it is unincorporated, it has its own zip code of 45897.[1] It lies at the intersection of U.S. Routes 30 and 68.
Williamstown was laid out in 1834 by John W. Williams, and named for him.[2] A post office called Eagle was established in 1834, and the name was changed to Williamstown in 1868. The post office service was suspended in 2007 and it was discontinued in 2009.[3]