Dai County, also known by its Chinese name Daixian, is a county in Xinzhou, Shanxi Province, China. Its county seat at Shangguan is also known as Daixian. The county has an area of 1,729 km2 (668 sq mi) and had a population of 178,870 at the time of the 2020 census. The county is the home of the AAAAA-rated Yanmen Pass Scenic Area along the Great Wall, as well as the Bianjing Drum Tower, the Ayuwang Pagoda, and the Zhao Gao Forest Park.