| Lake Dai 岱海 | |
| Location: | China |
| Pushpin Map: | Inner Mongolia |
| Basin Countries: | China |
| Length: | 25km (16miles) |
| Width: | 20km (10miles) |
| Area: | 160km2 |
| Depth: | 9m (30feet) |
| Max-Depth: | 15- |
| P: | Dàihǎi |
| W: | Tai Hai |
Lake Dai, also known by its Chinese name Daihai, is a lake in Liangcheng County, Ulanqab Prefecture, Inner Mongolia, China.
Lake Dai is a round lake with an area of about 160km2, measuring about 25km (16miles) from east to west and about 20km (10miles) from north to south. It has an average depth of about 9m (30feet) and a maximal depth of 15m-18mm (49feet-59feetm).
Under the Qin, Huangqi and Dai lakes formed the northern boundaries of Yanmen Commandery, marking part of the northern frontier of the Chinese empire.[1]