China proper and the Eighteen Provinces were terms in moderately wide use in the 19th century to indicate the core territories of China, inside the Great Wall and inhabited mainly by Han Chinese. Neither term is much used today, except by some historians.

There is no precise definition for "China proper"; it can be taken as just a synonym for the 18 provinces or interpreted in various other ways, all with the same general idea but some differences in the details. The term may be considered offensive by some people, an attempt to denigrate the Chinese state which controls several other areas — Manchuria, Inner Mongolia, Tibet, and Xinjiang — and in some cases has done so for centuries.

The Nationalists who ruled China 1912-49 had five bars on their flag, and the Communists who took over in 1949 have five stars on theirs; both are based on a notion of China as one state with five main ethnic groups:

• Han, ethnic Chinese
• Mongols
• Manchus
• various Muslim groups, mainly Hui and Uyghur
• Tibetan

One interpretation of "China proper" is as Han territory, excluding the other four.

The 18 provinces

The term "Eighteen Provinces" (一十八行省 Pinyin: Yīshíbā Xíngshěng, or 十八省 Shíbā Shěng) was used in Qing Dynasty (1644-1912) administration. The Ming Dynasty (1368-1644) used fifteen administrative divisions, and the Qing adopted and modified their system. Both the Nationalists and the Communists kept most of the Qing system and in general modern boundaries correspond to the older ones, though there have been some changes.

The 18 provinces in Qing times were:

• Anhui
• Fujian, which included Taiwan from 1683 to 1895
• Gansu, including what is now the separate area Ningxia
• Guangdong, including what is now the separate province Hainan.

Hong Kong and Macau were parts of Guangdong, then colonies of Western powers; they are now special administrative regions of China.

• Guangxi
• Guizhou
• Henan
• Hubei
• Hunan
• Jiangsu
• Jiangxi
• Shaanxi
• Shandong
• Shanxi
• Sichuan, including what is now Chongqing municipality
• Yunnan
• Zhejiang, including what is now Shanghai municipality
• Zhili, a province that no longer exists, though large parts of it are in modern Hebei. Other parts became the municipalities of Beijing and Tianjin

In the early 18th century the Qing re-arranged things along the southwestern border. The Tibetan province of Amdo became the Qing Empire province Qinghai and chunks from the Tibetan province of Kham were added to Sichuan and Yunnan.