The Western Han Dynasty defeated the Huns, why didn't Mobei be included in the territory?

Because Mobei, where Xiongnu is located, is a barren land, it is impossible to grow crops. Moreover, at that time, the Huns still had some residual strength, and Emperor Wu of the Han Dynasty could not move the people with peace of mind. It is really difficult to rule the vast land in Mobei.

At that time, although the Xiongnu had been driven out of Asia by Emperor Wu of the Han Dynasty, Mobei was desolate. The deep-rooted thought of the Han nationality is still that the land that can be cultivated is good and suitable for survival. Therefore, there is no intention to expand the territory. The purpose of the Great Wall is to resist the Huns. The existence of the Great Wall limited the expansion of the country, and even if it occupied Mobei, it was not good at management.

Huns are nomadic people, and their lives have always been mobile. Therefore, although the Xiongnu suffered heavy losses, after more than 100 years of recuperation, the Xiongnu still occupied the Western Regions, posing a great threat to the Eastern Han Dynasty.

Therefore, for such an unstable nation. No one dares to occupy their land easily, and there is no dangerous place to defend Mobei. When the Huns came, they had to be beaten passively.