This Illinois county has the largest African American population of any U.S. county, with about 1.5 million
[DOC] [TLE] Chicago-area black population drops as residents leave for South ... [PAR] Jun 24, 2016 ... Cook County in 2015 recorded the largest black population of any county in the 
U.S., a title it has held for several years, but its lead grows ... Cook County has 
about 1.3 million black residents.