I'm not saying the neighborhood I lived in was the worse in the US, but it was probably the worse in the Ohio/Kentucky/Indiana tri-county area. OTR (Over-the-Rhine). This is where the 2001 Cincinnati riots sprang from. It wasn't fun being in the middle of that, especially when you're white living in that neighborhood like I was.
http://www.youtube.com/watch?v=Oce3l90_Xrc