Dachengzi Town (simplified Chinese: 大城子镇; traditional Chinese: 大城子鎮; pinyin: Dàchéngzi Zhèn) is a town located in the Miyun District of Beijing, China.

[1] It sits within a valley, with Hongmenchuan and Qingshui Rivers flow through it.

'Big City') comes from Dachengzi Village, the place where the town's government resides in.

[3] By the end of 2021, Dachengzi Town administered 23 subdivisions: 1 community and 22 villages.

They are listed as follows:[4] Beijing-Chengde Expressway, Mixing Road and Beijing–Shenyang high-speed railway are the main roads within the town.