| Ryugase Group | |
| Type: | Geological formation |
| Age: | Late Santonian- Early Campanian ~ |
| Period: | Campanian |
| Prilithology: | Mudstone |
| Region: | Sakhalin Oblast |
| Coordinates: | 47.2°N 142.5°W |
| Paleocoordinates: | 51.9°N 130°W |
| Overlies: | Yezo Group |
| Extent: | Sakhalin Island |
The Ryugase Group is a geological formation on Sakhalin Island in far eastern Russia whose strata date back to the Late Cretaceous.[1]