Susa, also called Shushan was an ancient city in the lower Zagros Mountains about 250 km (160 mi) 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.
Shushan is first mentioned chronologically in Daniel 8:2 “And I saw in a vision; and it came to pass when I saw, that I was at Shushan in the palace, which is in the province of Elam; and I saw in a vision, and I was by the river of Ulai.” (Daniel 8:2).
Objections have been raised as to Daniel being at Shushan in the reign of Belshazzar, but the prophecy does not say definitely that he was there. It reads, “I saw in a vision; and it came to pass when I saw, that I was at Shushan.” He may have been there in a vision, or he may have gone there on the business of the king.
Esther was the queen of Ahasuerus (Xerxes), king of Persia, and resided at Shushan, and the various descriptions given in the book of Esther show that it was a place of wealth and luxury, and was of large extent. At a later date, Nehemiah was cupbearer to the king at Shushan (Nehemiah 1:1).