Qohestan (Persian: قهستان)[a] is a city in, and the capital of, Qohestan District of Darmian County, South Khorasan province, Iran.

[3] It also serves as the administrative center for Qohestan Rural District.

[4] Qohestan is a merger of the former villages of Asiyaban (آسیابان) and Derakhsh (درخش).

[6] The following census in 2011 counted 3,028 people in 741 households,[7] by which time the village had been raised to the status of a city.

[8] The 2016 census measured the population of the city as 2,322 people in 701 households.