New York is definitely the largest stronghold but there are a few select Zionist strongholds around the US. Florida is too broad to be classified as fully Zionist, specifially Miami and I believe it was Fort Lauderdale.

Other notable mentions are Los Angeles, Chicago and Philadelphia.

I think it’s just a numbers thing. I believe NYC has more Jewish people than Tel Aviv, let alone Miami, so yeah naturally there will be Zionists in there.