Daihai is a lake in Liangcheng County, within Ulanqab Prefecture in the Inner Mongolia region of China. It is also known by its Chinese name, Daihai, and the name "Lake Dai" is used in English references.
The lake lies in Liangcheng County, one of the counties administered under Ulanqab Prefecture in Inner Mongolia. Inner Mongolia is an autonomous region in northern China, and Ulanqab is one of its prefecture-level divisions.
Daihai is chiefly notable as a named lake of the region, and it is identified in reference sources by both its English name, Lake Dai, and its Chinese name, Daihai. It should not be confused with other places that share the name Daihai.