Shandan County (Chinese: 山丹县) is a county in Gansu Province, China, bordering Inner Mongolia to the north.

It is under the administration of the prefecture-level city of Zhangye.

It is an important site located on the ancient Silk Road.

The region's lakes provide water to the animals on the pastures.

Shandan County is divided to 6 towns, 2 townships and 2 others.