Manzhouli is a sub-prefecture-level city located in Hulunbuir prefecture-level city, Inner Mongolia Autonomous Region of the People's Republic of China (PRC). It is the PRC's busiest land port of entry. It has an area of 696.3 square kilometres (268.8 sq mi).
In ancient times the area was inhabited by many tribes that lived in Manchuria, including the Donghu, the Xiongnu, the Xianbei, the Khitan, the Jurchen, and the Mongols. From the early Qing Dynasty onwards the Argun River, which originates in this area, became the border between the China and Russia.