Over the last decade plus, I've worked at night and alone in a lot of these areas, so it's a reasonably informed opinion when I say that parts of the South Bronx and North Philly are more far dangerous than Camden, NJ -- No. 3 (right accross the river from Philly) as a whole.
It's just that there's little else left in Camden to balance out the bad. I can also tell you that if statistics for Chester, Pa had been included, it would have ranked as even worse than Camden, 'cause there's just nothing else left, and the cops there DO run scared, with good reason.
I also wonder how many of you not from the Northeast realized how funky parts of Charm City (Baltimore - No. 4) are.
Finally, Trenton, NJ (No. 39) is a walk in the park compared to any of these other places.