Ordos Plateau
In Chinese accounts, the Xiongnu first appear at Ordos in the "Yizhoushu" and "Shanhaijing" during the Warring States period before it was occupied by Qin and Zhao. It is generally thought to be their homeland, however when exactly they came to occupy the region is unclear, and it might have been much earlier than traditionally thought, as suggested by archaeological finds. As the Xiongnu expanded southward into Yuezhi territory around 160 BC under their leader Modun, the Yuezhi in turn defeated the Sakas (Scythians) and pushed them away at the Issyk Kul. It is thought the Xiongnu also occupied the Ordos area during the same period, when they came in direct contact with the Chinese. From there, the Xiongnu conducted numerous devastating raids into Chinese territory (167, 158, 142, 129 BC). The Han Dynasty started to fight the Xiongnu in the 2nd century BC under emperor Han Wudi, and colonized the area of the Ordos under Shuofang commandery in 127 BC. Prior to the campaign, there were already commanderies established earlier by Qin and Zhao until they were overrun by the Xiongnu in 209 BC.
Han–Xiongnu War
In 89 AD, General Dou Xian led a Han expedition against the Northern Xiongnu. The army advanced from Jilu, Manyi, and Guyang in three great columns. In the summer of 89, the forces—comprising a total of 40,000 troops—assembled at Zhuoye Mountain. Near the end of the campaign, Dou's forces chased the Northern Chanyu into the Altai Mountains, killing 13,000 Xiongnu and accepting the surrender of 200,000 Xiongnu from 81 tribes. A light cavalry of 2000 was sent towards the Xiongnu at Hami, capturing the region from them. General Dou Xian marched with his troops in a triumphal progress to the heartland of the Northern Xiongnu's territory and engraved an inscription commemorating the victory on Mount Yanran, before returning to Han. The Han victory in the campaign of 89 AD resulted in the destruction of the Xiongnu state. In 2017, a joint Sino-Mongolian archaeological expedition rediscovered the Inscription of Yanran in the Khangai Mountains of central Mongolia.