Just saw the following on Simple To Remember and thought it was interesting (if a few years old):
Metropolitan Tel Aviv, with 2.5 million Jews, is the world's largest Jewish city. It is followed by New York, with 1.9 million, Haifa 655,000, Los Angeles 621,000, Jerusalem 570,000, and southeast Florida 514,000.
Which is to say, in RDB-centric terms, that outside of Israel, the world's three largest Jewish cities are NY, LA, and SE Florida. I have lived in four places in my life; those are three of them.