Dídào

Didao stands on the eastern bank of the Tao River, where roads from the Wei valley meet the approaches to the Tibetan highlands. Established as a county in Qin times, it served for centuries as a regional administrative and military centre. Under the Jin it became the seat of Lintao Prefecture, a name retained by the Yuan and Ming. The town's strategic position placed it on routes between the Chinese interior, the Huang River country and lands farther south.

In the Qing, the prefectural seat was moved to Lanzhou and Didao was raised to a Zhou. Its local gazetteer discussed the ancient frontier wall said to have begun at Lintao, while distinguishing the older place of that name from Didao itself.