| Calvert Formation | |
|---|---|
| Stratigraphic range: Miocene | |
 Outcrops of the Calvert Formation at the Calvert Cliffs State Park | |
| Type | Formation |
| Unit of | Chesapeake Group |
| Underlies | Choptank Formation |
| Overlies | Old Church Formation |
| Location | |
| Region |  Maryland, Virginia, Delaware |
| Country | United States |
| Type section | |
| Named for | Calvert County |
The Calvert Formation is a geologic formation in Maryland, Virginia, and Delaware. It preserves fossils dating back to the early to middle Miocene epoch of the Neogene period. It is one of the three formations which make up the Calvert Cliffs, all of which are part of the Chesapeake Group.