| Official Name: | Williamsdale, Ohio |
| Settlement Type: | Census-designated place |
| Pushpin Map: | Ohio |
| Pushpin Label: | Williamsdale |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Ohio |
| Subdivision Type2: | County |
| Subdivision Name2: | Butler |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Area Total Km2: | 0.45 |
| Area Land Km2: | 0.45 |
| Area Water Km2: | 0.00 |
| Area Total Sq Mi: | 0.17 |
| Area Land Sq Mi: | 0.17 |
| Area Water Sq Mi: | 0.00 |
| Population As Of: | 2020 |
| Population Total: | 578 |
| Population Density Km2: | 1281.16 |
| Population Density Sq Mi: | 3321.84 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 600 |
| Coordinates: | 39.4419°N -84.5297°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 45011 |
| Area Code: | 513 |
| Blank Name: | FIPS code |
| Blank Info: | 39-85344[2] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2584372 |
Williamsdale is a census-designated place (CDP) in St. Clair Township, Butler County, Ohio, United States. The population was 578 at the 2020 census.
Williamsdale is located in the southern part of St. Clair Township, just north of the village of New Miami. It is in the valley of the Great Miami River but does not actually touch it.
U.S. Route 127 forms the western edge of the CDP, leading south into New Miami and thence into the city of Hamilton, and north to Eaton. The unincorporated community of Overpeck is directly to the northeast, along Hamilton Trenton Road.
According to the United States Census Bureau, Williamsdale has a total area of 0.45km2, all land.[3]