| Pentwater Lake | |
| Location: | Oceana County, Michigan |
| Coords: | 43.7692°N -86.4213°W |
| Inflow: | Pentwater River |
| Outflow: | Pentwater Lake Channel |
| Length: | 1.8miles |
| Width: | 4756feet |
| Area: | 431acres |
| Depth: | 27feet |
| Max-Depth: | 50feet |
| Volume: | 15900acre-ft |
| Shore: | 6.2miles |
| Elevation: | 581feet |
| Pushpin Map: | Michigan#USA |
| Cities: | Pentwater |
Pentwater Lake is a water body adjacent to the village of Pentwater, Michigan. Its primary inlet is the Pentwater River; its outlet is a man-made channel flowing into Lake Michigan.
Pentwater Lake has a surface area of, a maximum depth of, and an average depth of . The lake contains, a volume of water that would cover to a depth of . Its shoreline is long.