Henan and Hebei are now bounded by Zhanghe River, that is, from Hebei across Zhanghe Bridge to Henan. In ancient times, it was named after the Yellow River. Because the Yellow River has been diverted many times, there will still be places in Henan to the north of the Yellow River.

Hunan and Hubei are named because they are located in the north and south of Dongting Lake. Hunan is named because it is located in the south of Dongting Lake. It is named because it is located in the north of Dongting Lake.

Guangdong and Guangxi Since the Qin and Han Dynasties, Guangxin has become the most important place in Lingnan. The name of Guangdong and Guangxi began in the Song Dynasty, with the famous Guangxin County as the dividing line. The east of Guangxin is called Guangdong and the west of Guangxin is called Guangxi.

Shandong and Shanxi are bounded by Taihang Mountain. The so-called Shandong and Shanxi in ancient times were Shandong in the east and Shanxi in the west. In the modern administrative divisions of China, Zhongshan is not bordered by Shanxi in the east, but separated by Hebei in the middle, but it is customary to say that Taihang Mountain is the boundary mountain range between Shandong and Shanxi.