| Official Name: | Millfield, Ohio |
| Settlement Type: | Census-designated place |
| Mapsize: | 250px |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Ohio |
| Subdivision Type2: | County |
| Subdivision Name2: | Athens |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Population As Of: | 2020 |
| Population Total: | 311 |
| Population Density Km2: | auto |
| Population Density Sq Mi: | auto |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 633 |
| Coordinates: | 39.4342°N -82.095°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 45761 |
| Area Code: | 740 |
| Blank Name: | FIPS code |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2628933 |
Millfield is a census-designated place in northern Dover Township, Athens County, Ohio, United States. It had a population of 311 at the 2020 census.[2] It has a post office with the ZIP code 45761.[3] It is located near State Route 13 midway between Chauncey and Jacksonville. Route 13 formerly ran through the community, but a bypass relocated it close by.
A post office was established at Millfield in 1827.[4] Besides the post office, Millfield had a gristmill.[5]
The Millfield Mine disaster, the worst mine disaster in Ohio history,[6] occurred at Millfield in 1930.