The racial mix in the inner-cities is different than in the suburbs. You'll find more black residents in the cities and fewer in the suburbs. While African-Americans are a minority segment of the American population in general, they are not, for example, in many inner-city neighborhoods or schools, where they outnumber other races.
At some point in the past couple decades, the word "urban" became a "I am pretending to be polite to hide my prejudices" word for "black."
As you are probably aware, the issue of race in America is a very contentious one. Be very careful when mentioning race at all, unless there is a good reason to.
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