| Dubuque Formation | |
|---|---|
| Stratigraphic range: Ordovician | |
| Type | Formation |
| Underlies | Maquoketa Formation |
| Overlies | Galena Group |
| Location | |
| Region | Illinois, Minnesota |
| Country |  United States |
The Dubuque Formation is a geologic formation in Illinois, Iowa, Wisconsin and Minnesota. It preserves fossils dating back to the Ordovician period.