The birthplace of Zhangjiakou is the Baozili area now located in Qiaoxi District. The development here is a historical witness to the gradual prosperity of Zhangjiakou as a whole. The origin of the name Zhangjiakou is also closely related to this place. Baozili (also known as Xiabao) belonged to Xuanfu Town (now Xuanhua District (County)) of the capital during the Ming Dynasty and was the right guard of Wanquan. In the fourth year of Xuande (AD 1429), the commander Zhang Wen began to build a castle, named Zhangjiabao. The Zhangjia Fort is three feet tall and four miles and thirteen steps square. There is one gate in the southeast. It is called "Yongzhen Gate" in the east and "Chengen Gate" in the south. In the eighth year of Jiajing (AD 1529), guard Zhang Zhen opened a small gate in the north city wall, called "Xiaobeimen". Because the gate was as small as a mouth and Zhang Zhen opened and built it, it was called "Zhangjiakou". Mongols and Buryats call it "Kalgan".
Zhangjiakou was once named Zhangyuan. Zhangjiakou was renamed Zhangyuan after the National Government defeated the Beiyang warlords in 1928, and its original name was restored after liberation.