Kermanshah, formerly Bakhtaran, city in western Iran, capital of Kermanshah Province, in the Karkheh River valley. The city is the commercial center for grain and other produce of the countryside. Flour, textiles, refined oil, beet sugar, and carpets are produced here. Founded in the 4th century, Kermanshah has long been an important market center by virtue of its position on the caravan route from Hamadan to Baghdad. East of the city are the cliffs that bear the Behistun inscription, which became the key to deciphering several ancient Middle Eastern writings. Population (1996) 692,986.