Jingzhao (京兆) was a superior prefecture created in 713 during the Tang dynasty by converting Yongzhou (雍州). It lay north of the Qin Mountains in Shaanxi with Chang'an/Xi'an as its core. A census taken in 742 reported a total of 362,921 households (population: 1,960,188), while a census taken ca. 813 reported only 241,202 households.
References
Jingzhao Wikipedia(Text) CC BY-SA