| Grant Lake Formation | |
|---|---|
| Stratigraphic range: Late Ordovician | |
 Grant Lake Formation exposed in Boone County, Kentucky. | |
| Type | Formation |
| Underlies | Arnheim Formation and Bull Fork Formation |
| Overlies | Fairview Formation |
| Location | |
| Region |  Ohio Kentucky |
| Country |  United States |
The Grant Lake Formation is a geologic formation in Ohio and Kentucky. It preserves fossils dating back to the Ordovician period.