is a city in, and capital of, Damghan County, Semnan Province, Iran. At the 2006 census, its population was 57,331, in 15,849 families.
Damghan is situated 342 kilometres (213 mi) east of Tehran on the high-road to Mashad, at an elevation of 1,250 m (4,101 ft). The city trades in pistachios and paper almonds (kaghazi), with very thin shells, which are famous throughout the country. Despite possessing a history stretching back some 7,000 years, much of Damghan now lies all but forgotten beneath desert sand dunes : it is one of the most ancient cities on the Iranian plateau and still boasts many sites of historic interest. The oldest of these is Tappeh Hessar, a site lying to the southeast of the city and currently dominated by the ruin of a castle dating from the Sassanid period. An archeological dig here in 1996 revealed remains dating successively from the time of the Aryan settlement of the Iranian plateau (circa 4000 BCE) to the Median (728-550 BCE), Parthian (248-224 CE) and Sassanid (224-651 CE) dynastic periods. The Tarikhaneh was built as a fire temple during the Sassanid dynasty and converted into a mosque after the advent of Islam - and many other historical buildings belonging to Seljuks and other periods. Damghan was an important city in the Middle Ages, and was the capital of the province of Qumis (Qoomes), but was destroyed by the Afghans in 1723. Few remnants of that time remain; one is the ruined Tari-khaneh mosque with a number of massive columns and wood carvings and two minarets of the 11th century. The remains of Hecatompylos lie to the southwest of the city, extending from Forat, 26 kilometres (16 mi) south of Damghan, to nearly 32 kilometres (20 mi) west. On an eminence in the western part of the city are the ruins of a large square citadel with a small white-washed building, called Molud Khaneh (the house of birth), in which Fath Ali Shah was born (1772). The Tari-khaneh (c. 9th century), possibly the oldest known mosque in Iran, still stands in the city.