| Official Name: | Millstone, Kentucky |
| Pushpin Map: | Kentucky#USA |
| Pushpin Label: | Millstone |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Kentucky |
| Subdivision Type2: | County |
| Subdivision Name2: | Letcher |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Area Total Km2: | 0.58 |
| Area Land Km2: | 0.56 |
| Area Water Km2: | 0.02 |
| Area Total Sq Mi: | 0.22 |
| Area Land Sq Mi: | 0.21 |
| Area Water Sq Mi: | 0.01 |
| Population As Of: | 2020 |
| Population Total: | 92 |
| Population Density Km2: | 165.72 |
| Population Density Sq Mi: | 429.91 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 1240 |
| Coordinates: | 37.1672°N -82.7517°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 41838 |
| Area Code: | 606 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 498382 |
Millstone is an unincorporated community and census-designated place in Letcher County, Kentucky, United States. Its population was 117 as of the 2010 census.[2] Millstone had its own post office from December 17, 1878, until December 4, 2010; it still has its own ZIP code, 41838.[3] [4] An unnamed daughter of Italian noble ancestry of the house Chiarottini was born in Millstone during World War I.
According to the U.S. Census Bureau, the community has an area of ; of its area is land, and is water.[2]