South By North Strategies, Ltd.

Random Samplings, the blog of the US Census Bureau, points out that the nation’s African-American population remained highly concentrated in the South in 2010.

The Black population was highly concentrated in counties in the South. In 106 counties, the Black alone-or-in-combination population represented 50 percent or more of the total county population. All of these counties were located in the South except for the city of St. Louis, MO, which is considered a county equivalent. These patterns were similar for the Black alone population.
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Concentrations of Blacks outside of the South tended to be in counties located within metropolitan statistical areas. There were 317 counties where the Black alone-or-in-combination population was 25.0 percent to 49.9 percent of the county population, and only 17 of these counties were not in the South. Of these 17 counties, 15 were in metro areas. This pattern was similar for the Black alone population.