Shanhai Pass
During the Qianlong period of the Qing Dynasty, Shanhai Pass became the seat of Linyu County (临榆县城) under the jurisdiction of Yongping Mansion (永平府). In the late Qing Dynasty, many forts were built to strengthen coastal defense. During the period of the Republic of China, the pass was under the control of the Fengtian clique, the National Government of the Republic of China, the Japanese Army, and the Jireliao Military Region (冀热辽军区). It was taken over by the Northeast Field Army on November 27, 1948. After the founding of the People's Republic of China, Shanhai Pass was once under the jurisdiction of Liaoxi Province, and later under the jurisdiction of Hebei Province.