| Lake Piasa | |
| Settlement Type: | Unincorporated community |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Illinois |
| Subdivision Type2: | County |
| Subdivision Name2: | Jersey |
| Subdivision Type3: | Township |
| Subdivision Name3: | Piasa |
| Pushpin Map: | Illinois#USA |
| Pushpin Map Caption: | Location of Lake Piasa within Illinois |
| Coordinates: | 39.0228°N -90.1906°W |
| Elevation Ft: | 620 |
| Population As Of: | 2000 |
| Population Density Km2: | auto |
| Timezone1: | CST |
| Utc Offset1: | -6 |
| Timezone1 Dst: | CDT |
| Utc Offset1 Dst: | -5 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 1747829 |
| Area Code: | 618 |
Lake Piasa is an unincorporated community in Jersey County, Illinois, United States. It is located west of Brighton and about five miles north of Godfrey.