| Lago di San Casciano | |
| Location: | San Casciano dei Bagni (SI, Tuscany) |
| Coords: | 42.8398°N 11.8496°W |
| Pushpin Map: | Tuscany |
| Basin Countries: | Italy |
| Area: | 2km2 |
| Elevation: | 383m (1,257feet) |
Lago di San Casciano is a lake in the Province of Siena, Tuscany, Italy. At an elevation of 383 m, its surface area is 2 km2.
The lake is located in south of the municipality of San Casciano dei Bagni, near the borders with Lazio and the village of Trevinano.