| Nansi Lake | |
| Coords: | 34.6°N 129°W |
| Pushpin Map: | China Shandong |
| Basin Countries: | China |
Nansi Lake, or Weishan Lake, administrated by Weishan County and located in Shandong Province in China, is the largest freshwater lake in the north of the country. It consists of four connected lakes: Weishan, Zhaoyang, Nanyang, Dushan . It is 120 km long and 1266 square km in area.