According to historical records, there was once a castle in this city by the name of Haft Hessar (Seven Walls) which was said to have a thousand rooms and its grandeur equalled that of the Babylon Tower.

According to local Jewish traditions, the City of Hamedan is mentioned in the Bible, as the capital of Ancient Persia in the days of King Ahasuerus in the Book of Esther.

[10] Hamadan province has usually had net emigration, except for during the Iran-Iraq War when it took in a large number of refugees.

[10] This continuing emigration partly offsets the natural growth rate due to births.

[6] At the 1956 census, the territory of the province belonged to four different governorships (farmān-dāri): Hamadan, Malayer, and Nahavand, and Tuyserkan.

The population history and structural changes of Hamadan province's administrative divisions over three consecutive censuses are shown in the following table.

Among the major cities of the province are Asadabad, Bahar, Famenin, Hamadan, Kabudarahang, Malayer, Nahavand, Razan, and Tuyserkan.

[6] The lowest point in the province is 1,420 m above sea level, in the valley of the Gamasiab river near Nahavand.

[6] Most of the province's rivers originate in the snowmelt on Mount Alvand and then flow north or south.

[6] During the summer, when there is practically no rain, all but the largest rivers either dwindle to parched streams or dry up entirely.

[6] It receives several tributaries in the northern Alvand area, including the Siminarud, the Khaku, and the Farjin.

[6] Its reservoir has a capacity of 12 million cubic meters and it provides 2,400 liters of water per second, which is mostly used for agricultural irrigation.

[6] Hamadan province typically has relatively long, cold winters and mild summers.

[6] During the winter, the northern plains are exposed to strong winds that blow 4 meters per second on average.

[6] In the valleys between the province's mountains, there are springs and small lakes that form "semi-autonomous ecosystems" as home for migratory birds.

[6] For example, the seasonal marsh of Talab-e Aqgol, 20 km south of Malayer, is visited by 10 to 20 thousand birds every year during their route from the wetlands of Siberia and Scandinavia to warmer regions.

[6] Larger birds include royal eagles, golden eagles, falcons, hawks, owls, vultures; and larger mammals include wild goats, ibexes, wild boars, wolves, foxes, jackals, and hyenas.

[6] These numbers have been fairly stable, and in general the population levels of predators and prey are balanced.

[6] About a third of this farmland is irrigated, while the remaining two-thirds is under dry farming (in Persian: deym) and has far lower crop yields.

[6] Potatoes and sugar beets, though sown over a smaller area, have extremely high yields per hectare and as a result make up large shares of the province's produce.

[6] It is the biggest source of granite in the country, and it also has reserves of limestone, lead, iron ore, and zinc.

[6] In 2023, Ebrahim Ali Molla-Beigi, director general of the Exploration Affairs Office of the Iranian Ministry of Industries, Mining and Trade announced the discovery of 8.5 million tons of Lithium reserves in the province.

[6] Some of the more prominent trades include tanning, carpet weaving, ceramics production, and knitting.

[6] These larger factories produce things like agricultural and construction machinery, aluminum products, and steel.

[6] Food processing facilities include dairy products, canned fruits, sugar, and soft drinks.