Yu County, Hebei

The area was home to the capital of the state of Dai during the Spring and Autumn period of the Zhou dynasty.

[1] Daixian also served as the capital of Dai Commandery,[2] overseeing 11 or 13 counties in what is now northwestern Hebei and northeastern Shanxi.

Under the Eastern Han, the commandery seat was moved west to Gaoliu (near present-day Yanggao County in Shanxi).

[2] (A separate Dai Commandery was established by the Northern Wei in the 520s, with its seat at Pingcheng, just northeast of present-day Datong in Shanxi.

)[2] The city was a former garrison town during the Ming dynasty, serving as part of the defense system protecting the capital Beijing from Mongol Northern Yuan invasion.

Map including Yu County (labeled as YÜ-HSIEN (walled) 蔚縣 ) ( AMS , 1954)