Darreh Shahr (; also Romanized as Darreh-ye Shahr) is a town and the capital of Darreh Shahr County, Ilam Province, Iran. It's situated in a wide valley in the northern hillsides of Kabir Kuh ranges. At the 2011 census, its population was reported 24,961. The ruined ancient city of Darreh Shahr Ancient City is located in the southern part of Darreh Shahr. It has been extensively excavated by archaeologists. The Seymarah River flows to the north of the city. The city has a lot of potentials in agriculture, rich water supplies, green fields and dense forests.