Abstract: The Northern Wei Dynasty, building upon the Eastern Han Dynasty, successively established a Yong’an County under Xihe Prefecture and a Yong’an County under Pingyang Prefecture. Furthermore, it carved out a separate Yong’an County under the newly created Yong’an Prefecture. Additionally, an orphaned jurisdiction of Yong’an County for Xihe Prefecture was established to administer displaced populations. This complex administrative landscape resulted from evolving strategic needs. Such needs ranged from Emperors Xiaowen and Xuanwu’s efforts to stabilize local rule and appease the Shanhu people, to Emperor Xiaoming’s resettlement of refugees. It also included Erzhu Rong’s defense of Jinyang during Emperor Xiaozhuang’s reign. Notably, a historical error locating the seat of Yong’an County of Xihe Prefecture east of Lingshi County has persisted since the Tang Dynasty. This mistake has subsequently influenced modern historical geography research. The Eastern Wei Dynasty established Yong’an County, an orphaned jurisdiction, in Wucheng Prefecture, where Pingyang Prefecture lay. Thus, a situation where four distinct Yong’an administrations coexisted came onto being. The Northern Zhou Dynasty largely followed the Northern Qi system but abolished Wucheng Prefecture. The Sui Dynasty gradually eliminated these displaced administrations and renamed Yong’an County of the Pingyang Prefecture to Huoyi County. During the Tang Dynasty, the Xihe Yong’an County was renamed Xiaoyi County. Consequently, the name Yong’an disappeared from the historical evolution of the region along River Fen.