The area was a strategic choke point in ancient and medieval China, controlling access between the valleys of central Shanxi and the Eurasian Steppe.

This made it the scene of various important battles, extending into World War II, and the area around the gatehouses and this stretch of the Great Wall is now a AAAAA-rated tourist attraction.

He organized these conquests as the commanderies of Yunzhong, Yanmen, and Dai and, by around 300 BC, had begun erecting earthen defensive works to protect his new holdings from other nomads from the Eurasian steppelands.

[8][9] Although Zhao's Yanmen Commandery was named after the pass, whose premodern importance for accessing the valleys of central Shanxi caused it to be scene of many battles throughout Chinese history,[1] the ramparts raised under King Yong did not run through it but along the northern extent of his territory closer to today Hohhot in Inner Mongolia.

[1] At some point during the reign of the First Emperor of Qin (221–210 BC), a Chu noble named Ban Yi (斑 or 班壹, Bān Yī) fled north to the Loufan near Yanmen.

[12] By the early Han Dynasty, his clan had grown rich through herding and trading thousands of heads of cattle and horses,[13] to the point that they may have formed a microstate of their own.

[17] The Ban clan ultimately left the tumultuous area and used their accumulated wealth to rise to prominence among the officials of the Eastern Han by the 1st century AD.

[19] The Sui (581–618) rulers regarded the Great Wall as an essential line of defense and ordered large-scale repairs 7 times, but their successors the Tang (618–907) expanded China far to its north, and allowed it to fall into disuse and decay.

In 980, roughly 100,000 nomad horsemen of the Khitan Empire (known to the Chinese as the Liao) invaded Shanxi under their general Li Chonghui (t 李重誨, s 李重诲, Lǐ Chónghuì) and on behalf of their defeated allies.

Arriving before Yanmen, Li and his men were encircled and catastrophically defeated by the Song generals Yang Ye and Pan Mei[20] outside the fortress at Baicao Lingkou.

[21] The victory killed the Khitan emperor's brother-in-law Xiao Chuoli (t 蕭啜裏, s 萧啜里, Xiāo Chuòlǐ), won Song innumerable horses and war equipment, and secured its new conquests and northern border.

[23] Following the war, Yanmen Pass was reckoned as part of the boundary of China's "Third Front", which was used by national authorities in planning infrastructure investment and military defenses.

[6] They were excavated by Japanese archaeologists in the early 20th century and have been studied by the Chinese in the 1980s; a tomb robber around that time was caught and exposed that the mounds were not for local elites but for group burial in urns.

[1][2] The Battle of Yanmen Pass is an important moment in the Chinese legends, folktales, and plays collectively known as The Generals of the Yang Family.