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.
Yueban
Between 155 and 166, the Xianbei or Syanbi (Ch. , Wade–Giles Hsien-pi, Hsien-pei), a former vassal tribe of the Xiongnu, united under Tian-Shih-huai conducted a series of campaigns against Northern Xiongnu, eventually defeating them and forcing them to flee west, which started a series of Xiongnu migrations (93 CE - circa 380 CE) westward to southern Siberia and Central Asia. (The Xiongnu have often been linked to the Huns that later invaded Europe from the Eurasian steppe, although the link has never been conclusively established. Likewise the Yueban of late antiquity have sometimes been known as the "Central Asian Huns".)