This Illinois county has the largest African American population of any U.S. county, with about 1.5 million
Its county seat is Chicago, the largest city in 
Illinois and third-most populous ... Cook County's population is larger than that of 
29 individual U.S. states and... [DOC] [TLE] 2010 Census Shows Black Population has Highest Concentration in ... [PAR] Sep 29, 2011 ... Of the total U.S. population of 308.7 million on April 1, 2010, 38.9 million people, 
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