Zanjan (Persian: زنجان, ; Azerbaijani: زنگان) is the capital of Zanjan Province in Iran. It lies north-west of Tehran on the main highway to Tabriz and Turkey and approximately from the Caspian Sea. The city is located about 20 kilometers south of the Qaflankuh Mountain Range. At the 2016 census, its population was 521,302 which is the 20th largest city in Iran. The population of Zanjan consists mostly of Iranian Azeris who can also speak the Azerbaijani language. The entire province has 21,733 square kilometers.