The Guantian site in Sangzhi county, Zhangjiajie city, Hunan province, was first excavated in 2015 and found to have iron casting ruins from the Han (206 BC-AD 220) and Jin (265-420) dynasties. During the excavation from 2020 to 2022, it was confirmed that the site was a multi-metal production workshop and the largest iron casting site of that period found in South China. The archaeological finds help fill the research gap on ancient iron ware casting and production.