Dai Commandery was a commandery (jùn) of the state of Zhao established c. 300 BC and of northern imperial Chinese dynasties until the time of the Emperor Wen of the Sui dynasty (r. AD 581–604). It occupied lands in what is now Hebei, Shanxi, and Inner Mongolia. Its seat was usually at Dai or Daixian (near present-day in Hebei), although it was moved to Gaoliu (present-day Yanggao in Shanxi) during the Eastern Han.