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.
Xiongnu
Over the past decade, Chinese archaeologists have published several reviews regarding the results of excavations in Xinjiang. They imply the Xiongnu's supreme ruling class. Particularly interesting are the tombs in the cemetery at Heigouliang, Xinjiang (the Black Gouliang cemetery, also known as the summer palace of the Xiongnu king), east of the Barkol basin, near the city of Hami. By typing results of DNA samples during the excavation of one of the tombs, it was determined that of the 12 men: 6 Q1a* (not Q1a1-M120, not Q1a1b-M25, not Q1a2-M3), 4 Q1b-M378, 2 Q* (not Q1a, not Q1b: unable to determine subclades):