Green’s Dictionary of Slang

(US black) the African-American areas of Chicago.

[1931		F.M. Davis [poem title] Chicago’s Congo’].
1936		Plaindealer (Kansas City) 21 Feb. 3/2: A word to Dan Burley: Your ‘Chicongo’ seems a direct steal from ‘Chicago’s Congo’ first printed in [...] 1931.
1936		D. Burley in Chicago Defender 14 Mar. 11: Peculiar sitiation exists in Chicongo right now.
1947		D. Burley N.Y. Amsterdam News 2 Aug. 17: Your Cousins in Chicongo [...] I found that the Chicongonese and the Harlemese have the same problem.
2010		Urban Dict. 15 Aug. 🌐 chicongo making fun of Chicago due to it's high concentration of niggers (Congo is a war torn country in Africa).