China proper is bounded north by Mongolia, west by Tibet and Kyrgyzstan, southwest by Burma, south by Tonkin (northern Vietnam) and the Gulf of Tonkin, southeast by the South China Sea, east by the East China Sea, the Yellow Sea, Bohai Sea and Manchuria. Its area is approximately 1,500,000 kmē.
Since Qing Dynasty, China proper, also known as the Eighteen Provinces (一十八行省 Pinyin: Shiba Xingsheng, or 十八省 Shiba Sheng), consist of:
For Outer Chinese regions of Fengtian (now Liaoning), Jilin, Heilongjiang, Xinjiang, and Mongolia, the military leaders are generals (將軍) and vice-tudong (副都統), and civilian leaders are heads of the leagues (盟長).
In 1878, Xinjiang became a province, in 1909, Fengtian, Jilin, and Heilongjiang were made provinces as well. As a result, there were 22 provinces in China (Outer China and China proper) near the end of the Qing Dynasty.
The entire China proper was divided into several thousand counties at the beginning of the 20th century.
Outer China was the homeland of many "barbaric" tribes, like the Xiongnu and other minority ethnic groups in Chinese history, some of which tried to invade Chinese, but sometimes get Sinicized partially or wholly.