Reference: Shushan, or Susa
Smith
Shu'shan, or Su'sa
(a lily), is said to have received its name from the abundance of the lily (shushan or shushanah) in its neighborhood. It was originally the capital of the country called in Scripture Elam, and by the classical writers Susis or Susiana. In the time of Daniel Susa was in the possession of the Babylonians, to whom Elam had probably passed at the division of the Assyrian empire made by Cyaxares and Nabopolassar.
The conquest of Babylon by Cyrus transferred Susa to the Persian dominion; and it was not long before the Achaemenian princes determined to make it the capital of their whole empire and the chief place of their own residence. According to some writers the change was made by Cyrus; according to others it had at any rate taken place before the death of Cambyses; but, according to the evidence of the place itself and of the other Achaemenian monuments, it would seem most probable that the transfer was really the work of Darius Hystaspes. Nehemiah resided here.
Shushan was situated on the Ulai or Choaspes. It is identified with the modern Sus or Shush, its ruins are about three miles in circumference. (Here have been found the remains of the great palace build by Darius, the father of Xerxes, in which and the surrounding buildings took place the scenes recorded in the life of Esther. The great central hall was 343 feet long by 244 feet wide. The king's gate, says Schaff, where Mordecai sat, "was probably a hall 100 feet square, 150 feet from the northern portico. Between these two was probably the inner court, where Esther appeared before the king." --ED.)