| Chain O'Lakes State Park | |
| Iucn Category: | III |
| Map: | Illinois#USA |
| Map Width: | 225 |
| Location: | Lake and McHenry counties, Illinois, United States |
| Nearest City: | Spring Grove, Illinois |
| Coordinates: | 42.4589°N -88.1742°W |
| Established: | 1945 |
| Governing Body: | Illinois Department of Natural Resources |
Chain O'Lakes State Park is a 2793acres Illinois state park at the inlet of the Fox River into the Chain O'Lakes in Lake and McHenry counties, in the suburban wildlife of Chicago, Illinois, United States.
It is one of the centerpieces of the proposed Hackmatack National Wildlife Refuge.