The Houchengzui stone city site in Qingshuihe county, Inner Mongolia autonomous region, covers about 1.38 million square meters and dates back around 4,200 to 4,400 years. It represents the highest-ranking, largest-scale, and most heavily fortified stone city of the Longshan Culture period discovered in Inner Mongolia autonomous region to date.
Excavations have revealed remnants such as city walls, city gates, foundation structures, platform, trenches, underground tunnels, tombs, and various relics, including jade ware, pottery, stone tools and bone artifacts. These findings illuminate the settlement layout of Houchengzui stone city, providing credible evidence for the evolution and development of fortified systems and the origin of organizational systems in ancient Chinese cities.