Yùzhou or Yù Prefecture (蔚州), also translated as Weizhou or Wei Prefecture, was a zhou (prefecture) in imperial China, centering on modern Yu County, Hebei, China. It was one of the Sixteen Prefectures ceded by Later Jin to the Khitan-ruled Liao dynasty.
Yuzhou, a town in modern Yu County, retains its name.
Yù Prefecture Wikipedia
The administrative region of Yuzhou in the Tang dynasty is the border area of western Hebei and northern Shanxi:Under the administration of Zhangjiakou, Hebei:
Under the administration of Baoding, Hebei:
Under the administration of Datong, Shanxi: