Beihai (北海) referred to the north-eastern coastal region of Qing Province on the Shandong Peninsula. The area was administered as Beihai Commandery (北海郡), which included counties such as Gaomi.
Zheng Xuan was born at Gaomi in Beihai in 127 and became one of the most influential Confucian commentators of the late Han. For the commandery’s administration, scholars, and role in the warlord period, see Beihai Commandery.