Dan County is located in the eastern part of Henan Province, neighboring Anhui Province to the east. According to legend, during the Spring and Autumn Period, Laozi, the founder of Taoism, refined his "dan" here, so it was called "Dancheng", and later harmoniously called Dancheng. It belonged to Li and Chen in the Western Zhou Dynasty, Chu in the Warring States period, and Bitter County and Xiang County in Chen County in the Qin Dynasty.

Western Han Dynasty set Ningping, Yilu two counties (now Dancheng County, Ningping Town, Yilu Town). Sui Kaihuang six years (586 years) set Dan County (today's county seat), the beginning of the Tang Dynasty was abolished, and later reset Dan County.