Erlonghu ancient city site, located in beiweizitun, Erlongshan village, Shiling Township, Lishu County, Jilin Province, is the northern border city of Yan state in the late Warring States period, more than 2300 years ago.

Erlong Lake ancient city site, square in plan, covers an area of about 35000 square meters. The city wall is made of loess mixed with sand and stone. There are turrets and Wengcheng, and there are rammed earth platforms in the middle of the northern part of the city.

The site of Erlonghu ancient city contains iron wok, iron harness, copper arrow, pottery kettle, pot, Zun and other artifacts of Warring States period, as well as architectural components such as shingles and tube tiles with rope pattern.

The characteristics of pottery in Erlonghu ancient city site have obvious style characteristics of Yan culture in the Warring States period, which provides important materials for studying the close relationship between Yan culture and Northeast China in the Warring States period.