| Lake Viljandi | |
| Location: | Viljandi County |
| Coords: | 58.35°N 25.5931°W |
| Pushpin Map: | Estonia |
| Inflow: | Valuoja, Uueveski Creek |
| Outflow: | Raudna |
| Basin Countries: | Estonia |
| Length: | 4.33km (02.69miles) |
| Width: | 435m (1,427feet) |
| Area: | 1.58km2 |
| Max-Depth: | 11m (36feet) |
| Elevation: | 42.35m (138.94feet) |
| Cities: | Viljandi |
Lake Viljandi (Estonian: Viljandi järv) is a lake in Viljandi County, Estonia. The lake lies in a deep valley below the town of Viljandi. It has a depth of 11m (36feet), length of 4.6km (02.9miles), width of 400m (1,300feet), and area of 1.55sqkm.[1] Uueveski and Valuoja creeks and a number of springs flow into the lake. The Raudna River flows from the southwestern part of the lake. The main fish in the lake are bream, roach, perch, and pike. The lake and its shores make up the Viljandi landscape protection area.
The Grand Race around Lake Viljandi is held annually.