North and South China

Northern China and southern China are two approximate regions within China. The exact boundary between these two regions are not precisely defined. Nevertheless, the self-perception of Chinese people, especially regional stereotypes, has often been dominated by these two concepts, given that regional differences in culture and language have historically fostered strong regional identities (simplified Chinese: 乡土; traditional Chinese: 鄉土; pinyin: xiāngtǔ) of the Chinese people.

Often used as the geographical dividing line between northern and southern China is the Huai River–Qin Mountains Line. This line approximates the 0 °C January isotherm and the 800 millimetres (31 in) isohyet in China.

Culturally, however, the division is more ambiguous. In the eastern provinces like Jiangsu and Anhui, the Yangtze River may instead be perceived as the north–south boundary instead of the Huai River, but this is a recent development.

There is an ambiguous area, the region around Nanyang, Henan, that lies in the gap where the Qin has ended and the Huai River has not yet begun; in addition, central Anhui and Jiangsu lie south of the Huai River but north of the Yangtze, making their classification somewhat ambiguous as well. As such, the boundary between northern and southern China does not follow provincial boundaries; it cuts through Shaanxi, Henan, Anhui, and Jiangsu, and creates areas such as Hanzhong (Shaanxi), Xinyang (Henan), Huaibei (Anhui) and Xuzhou (Jiangsu) that lie on an opposite half of China from the rest of their respective provinces. This may have been deliberate; the Mongol Yuan Dynasty and Han Chinese Ming Dynasty established many of these boundaries intentionally to discourage regionalist separatism.

...
Wikipedia