| Place Name | Great Mills |
| Place Type | Unincorporated |
| ZIP Code(s) | 20634 |
| County | Saint Marys County |
| Area Code(s) | 240,301 |
| Timezone | Eastern Standard Time (EST) |
| Population () | |
| Metro/Micro Stats Area | California-Lexington Park, MD |
| US Congressional District(s) | Maryland 5th |
| House of Delegates Districts | 29B |
| State Senate Districts | 29 |