Map Introduction

During the Western Jin Dynasty, You Province and Ping Province underwent the following key changes in their historical evolution:

Evolution of You Province

In the Western Jin period, You Province continued the administrative structure of the Cao Wei era. Its provincial seat was located in Ji County (modern Beijing). Its territory covered the northern part of modern Hebei Province and the entire area of modern Beijing, administering several commanderies and counties, including important administrative districts such as Fanyang and the Yan Principality.

Background of Ping Province's Establishment

In the early Western Jin, Ping Province was not yet a formal provincial-level administrative division. However, during the Cao Wei period, the Inspector of You Province had occasionally exercised separate jurisdiction over the Ping region, though it never formed an independent administrative entity. After the Western Jin unification, and to strengthen frontier management, the Ping region—originally part of You Province—was formally established as an independent provincial-level administrative unit. The precise timing of this establishment, however, is not clearly recorded in historical sources.

Characteristics of the Evolution

• Administrative Adjustments: The Western Jin merged the Cao Wei's Jing Province and Yang Province into Jiang Province. Furthermore, it created Qin Province from Liang Province, Liang Province and Ning Province from Yi Province, and finally established Ping Province from You Province. This culminated in an administrative framework of twenty-one provinces.

• Characteristics of Military Administration: The Western Jin continued the Cao Wei system where the Provincial Inspector (Cishi) managed both civil affairs and military authority. For instance, the Inspector of You Province typically also held the title of Area Commander (Dudu), responsible for military command within his own province and several adjacent ones. The extent of his authority and responsibility varied depending on his specific level of imperial commission.

• Changes in Household Registration and Commanderies/Counties: During the Taikang era (280-289 AD) of the Western Jin, the empire comprised 19 provinces, over 170 commanderies, and more than 1,200 counties. However, the registered household count showed a decrease compared to the Eastern Han period, a phenomenon linked to population loss caused by warfare.

The information above synthesizes the features of administrative adjustment and historical continuity during the Western Jin, reflecting the complexity of local administration during this period.