Susa is an ancient city in the lower Zagros Mountains about 250 km east of the Tigris, between the Karkheh and Dez Rivers in Iran. One of the most important cities of the Ancient Near East, Susa served as the capital of Elam and the Achaemenid Empire, and remained a strategic centre during the Parthian and Sasanian periods.
The site currently consists of three archaeological mounds, covering an area of around one square kilometre. The modern Iranian town of Shush is located on the site of ancient Susa. Shush is identified as Shushan, mentioned in the Book of Esther and other Biblical books.