| Isachsen Formation | |
| Type: | Formation |
| Period: | Aptian |
| Age: | Aptian ~ |
| Region: | Nunavut |
| Coordinates: | 76.1°N -109°W |
| Paleocoordinates: | 71.5°N -20.5°W |
| Subunits: | Walker Island member |
| Overlies: | Christopher Formation |
The Isachsen Formation is a geologic formation in Nunavut. It preserves fossils of Polycotylidae indet., dating back to the Aptian stage of the Cretaceous period.