the Genovese, Luchese, Scrafo, Decavalcante and other mob families all are or have been very, very strong in New Jersey. The Sopranos is a kind of 'collage' (a little of this and a little of that) family but does not size up much.
There are also russian, cuban, sendero luminoso and other crime 'famiglias' from non-traditional places. Cannot be called mafia, because this word is more Cosa Nostra (italian) than anything. But still.... careful there. this is not the place to discuss crime.
PS... Google crime syndicates, cosa nostra, italian maffia ... in nj and you will get tons of stuff... lovely.