Mei County
Fa Zheng's ancestral home was in Mei County (), Youfufeng Commandery (), which is in present-day Mei County, Shaanxi. His ancestor was Tian Fazhang, who is historically known as King Xiang of the Qi state in the Warring States period. Tian Fazhang's descendants changed their family name from "Tian" to "Fa" after the fall of Qi in 221 BCE.