About the history of the Loop Corridor

About the history of the Hetao Corridor Regarding this issue, I think that in 127 BC, the Xiongnu nobles invaded Shanggu (now Huailai County, Hebei Province) and Yuyang with 20,000 horsemen. Emperor Wu of the Han Dynasty sent young general Wei Qing to lead 30,000 cavalry out of Yunzhong (now Tuoketuo County, Inner Mongolia) and west to Longxi (now eastern Gansu) to recover the Hetao area and eliminate the military strongholds invaded by the Huns. Started in March 121 BC. Huo Qubing led 10,000 cavalrymen from Longxi, fought with the Xiongnu cavalry at the foot of Gaolan Mountain, and pursued them for more than 500 kilometers across Yanzhi Mountain (in today's Shandan County, Gansu Province). In the summer, Huo Qubing led tens of thousands of cavalry and marched more than 1,000 kilometers to the foothills of the Qilian Mountains, dealing a heavy blow to the Xiongnu nobles. Emperor Wu of the Han Dynasty established four counties in the Hexi region: Wuwei, Jiuquan, Zhangye, and Dunhuang. He immigrated 100,000 people to settle in the Hexi region and recovered the Hexi Corridor.