Linked above is a map showing the location of officially recognized "hate groups" as listed by the Southern Poverty Law Center.
I would dispute the inclusion of the Nation of Islam and the New Black Panther Party as "black separatist groups" on this list. The NOI has toned down it's separatist rhetoric, though black nationalism is still a theme. It is rare that you will hear a Nation minister refer to white folks as devils like they did 40 years ago.
The New BPP is probably on this list because it was chaired by the late Khalid Muhammad, a former NOI minister who made many of the NOI's most recent "hate" speeches (receiving condemnation from Clinton andGore in 1993). Khalid died from a suspicious illness in 2001. Most of the New BPP's activities have centered around community activism and videotaping police patrols in several urban cities.
The United Nuwabian Nation is a strange cult-like organization that mixes a philosophy of radical Islam, black separatism and outer space mythology in their creed. Weird folks indeed, but dangerous? Well, they were stockpiling guns in their rural Georgia headquarters until the police raided a few years ago. I can't vouch for those cats.