Where was Nehemiah when he received news that Jerusalem's wall was broken down?

Answer: The citadel of Susa

In the month of Chislev, in the twentieth year, Nehemiah was in the citadel of Susa when Hanani came with news of Jerusalem.

“These are the words of Nehemiah son of Hacaliah: In the month of Chislev, in the twentieth year, while I was in the citadel of Susa,”— Nehemiah 1:1 (BSB)