The state of Qin fortified the pass in 361BC as its eastern border,[4] protecting access to their homeland from the armies of the other Warring States competing to succeed the Zhou. It continued to protect the Guanzhong area of the Qin and Western Han empires. Under the Eastern Han that succeeded Wang Mang's "Xin dynasty", its fortifications protected the capital Luoyang in the other direction, staving off attacks coming from the west and northwest.
After the fall of the Han and rise of the Three Kingdoms, the Hangu Pass lost most of its importance as the primary fortifications moved a little west to Tong Pass.
Discovery of Han dynasty Hangu Pass site
Between 2012 and 2013 a team from the Luoyang Cultural Relics and Archaeological Institution conducted an archaeological excavation at the site in Xin'an, Luoyang, on an area of more than 3,000 square meters. This excavation brought several roads, platforms and walls to light.[5]
Today, the archaeological site of the Hangu Pass in Xin’an is a museum park.
Hangu Pass in fiction
In the manga series Kingdom by Yasuhisa Hara, the Hangu Pass was the last chokepoint that Li Mu and his Coalition Army needed to overcome in order to defeat Qin. Their attacks were repelled with great losses, forcing Li Mu to make a decision of attacking Xianyang via Zui.