New census data show that it's not the South that's segregated—northern cities are the nation's most racially segregated urban areas. Salon.com put together this super informative slideshow of the 10 most segregated cities. Here's LA:

I'll save you the guessing: Portland's not on the list. But, what comes in at a surprise number one? Milwaukee. The reason why has to do with historic redlining, but also current public transit politics:

Nationwide, blacks have been concentrated in the inner city, far away from where new jobs are created. Yet the case of Milwaukee is extreme: 90 percent of the metro area's black population lives in the city. Making matters worse, suburban whites are notably hostile to building any form of public transit to connect city people to suburban jobs, further exacerbating segregation's ill effects.

If you're wondering if this can somehow, some way, be blamed on union-busting Wisconsin Gov. Scott Walker, the answer is yes. Walker took the lead in a campaign against public transit to connect the suburbs to the city during his time as county executive. He thought the funds would be better spent on highways.