| Blackett Lake | |
| Pushpin Map: | Ontario |
| Location: | Thunder Bay District, Ontario |
| Coords: | 50.4639°N -88.7544°W |
| Outflow: | Blackett Creek |
| Basin Countries: | Canada |
| Length: | 1.7km (01.1miles) |
| Width: | 1.4km (00.9miles) |
| Elevation: | 325m (1,066feet) |
Blackett Lake is a lake in Thunder Bay District, Ontario, Canada and the source of Blackett Creek. It is 1.7km (01.1miles) long and 1.4km (00.9miles) wide, and lies at an elevation of 325m (1,066feet) about 26.5km (16.5miles) northeast of the community of Armstrong.