The state was based in the walled City of Ji, or Jicheng, located in the modern day Guang'anmen neighborhood of southwestern Beijing.
[1] According to Sima Qian's Records of the Grand Historian, King Wu of Zhou, in the 11th year of his reign, deposed King Zhou of Shang and conferred titles to nobles within his domain, including the rulers of the city states Ji and Yan.
According to the Book of Rites, King Wu of Zhou was so eager to establish his legitimacy after his battle victory over the Shang that before dismounting from his wagon, he named the descendants of the Yellow Emperor to the State of Ji.
[3] The capital of the state was the walled City of Ji or Jicheng (t 薊城, s 蓟城, Jìchéng).
The city was located in the southwestern part of present-day Beijing, just south of Guang'anmen in Xicheng and Fengtai Districts.