Hongcheng is a town in Yongdeng County, which falls under the administration of Lanzhou, the capital of Gansu Province in China. It lies along the east bank of the Zhuanglang River, a left tributary of the Yellow River.
The town's position on the river's eastern side places it within the broader Zhuanglang River valley, a drainage area that feeds into the Yellow River system. Yongdeng County surrounds Lanzhou's urban core to the north and west, and Hongcheng sits within this county's administrative territory.
Note that the name Hongcheng is shared by other places, including a district in Nanchang, Jiangxi. The Hongcheng described here is specifically the town in Gansu, distinguished by its location in Yongdeng County and its setting on the Zhuanglang River.