| Guelph Lake | |
|---|---|
 Swimmers at Guelph Lake | |
  Guelph Lake | |
| Location | Guelph, Ontario |
| Coordinates | 43°36′N 80°14′W / 43.600°N 80.233°W |
| Type | artificial lake |
| Primary inflows | Speed River |
| Primary outflows | Speed River |
| Basin countries | Canada |
Guelph Lake is a man-made reservoir on the Speed River, in the Township of Guelph/Eramosa. It is located upriver and slightly northeast of the city of Guelph, Ontario. The reservoir was created in 1974, with the construction of the Guelph Lake dam. The site is part of a 1,608 hectares (3,970 acres) conservation area maintained by the Grand River Conservation Authority.