Darrehshahr is a city located in the southeastern part of Ilam province in Iran. It serves as the capital for both Darreh Shahr County and its Central District. Geographically, the city is situated in the northern foothills of the Kabir Kuh ranges.
According to the 2016 census, the city has a population of 21,900 residents. Based on these figures, it ranks as the second-largest city within Ilam province.