Hamadan Province ( Ostān-e Hamadān) is an Iranian province located in the Zagros Mountains. Its capital is the city of Hamadan. The province covers an area of 19,546 km2. According to the National Census held in 2006, Hamadan had a population of 1,674,595 in 427,675 households. The following census in 2011 counted 1,758,268 people in 506,191 households. In 2014, Hamadan province was placed in Region 4. The latest census in 2016 revealed a slight decrease in the population to 1,738,234 in 538,803 households. Among the major cities of the province are Asadabad, Bahar, Famenin, Hamadan, Kabudarahang, Malayer, Nahavand, Razan, and Tuyserkan. History Hamadan province is one of the most ancient parts of Iran and its civilization. Relics of this area confirm this fact. Today's Hamedan is what is left of Ecbatana, the Medes' capital before they formed a union with the Persians. The poet Ferdowsi says that Ecbatana was built by King Jamshid. According to historical records, there was once a castle in this city by the name of Haft Hessar (Seven Walls) which had a thousand rooms and its grandeur equalled that of the Babylon Tower. The structures of city are related to Diya Aku, a King of the Medes from 700 BC. According to Greek records, this territory was called 'Ekbatan' and 'Hegmataneh' by this King, thus transformed into a huge capital. During the Parthian era, Ctesiphon became capital of Persia, and Hamedan became the summer capital and residence of the Parthian rulers. After the Parthians, the Sassanids constructed their summer palaces in Hamedan as well. In the year 633 when the war of Nahavand took place and Hamadan came into the hands of the invading Arabs, at times it thrived and at times it declined and witnessed hardships. During the Buwayhids, it suffered plenty of damages. In the 11th century, the Seljuks shifted their capital from Baghdad to Hamadan once again. The city of Hamadan was always at risk during the rise and fall of powers. It was completely destroyed during the Timurid invasion. However, during the Safavid era the city thrived once more. In the 18th century, Hamadan surrendered to the Ottomans, but Hamadan was retaken by Nader Shah Afshari, and under the peace treaty between Iran and the Ottomans it was returned to Iran. The city of Hamadan lay on the Silk Road and even in recent centuries enjoyed good prospects in commerce and trade