Why doesn't Xiangyuan develop northward?

The mountains are in the north. According to Baidu map information, xiang yuan belongs to Changzhi City, Shanxi Province, close to Taihang Mountain, and the northern edge of Xiangyuan County is a mountainous area, which is not suitable for development. In the early Warring States period, Zhao Xiangzi built a city here, hence the name xiang yuan. The county was founded in the early Western Han Dynasty, with a history of more than 2,400 years.