Africa, n. — Green’s Dictionary of Slang

Africa n.

(US) anywhere mainly populated or used by the black community [neg. stereotyping].

1891		J.A. Riis How the Other Half Lives 68: The old ‘Africa,’ west of Broadway [...] is rapidly changing its character.
1932		P.G. Cressey Taxi-Dance Hall 35: Africa – The Black Belt, especially the colored cabarets.

go back to Africa (v.)

(W.I., Guyn.) of a light-skinned man, to marry a woman whose complexion is much darker than his own.

1996

carry the war into Africa (v.) [press the war into Africa]

to take things further, to the extreme.

1840		Eve. Signal (NY) 25 Jan. n.p.: Mr Sibley replied to Col. Y. with great spirit and effect, carrying the war into Africa.
1851		Western Police Gaz. 29 Mar. n.p.: [W]ith Mayor Mickle’s banner ‘Beware of Mock Auctions,’ he will press the war into Africa.
1857		Venus’ Miscellany (NY) 31 Jan. n.p.: [of sexual intercourse] She allowed me to take many liberties [but] she had always repelled my endeavours to carry the war into Africa.
1866		NY Wkly Day Bk 6 Oct. n.p.: [T]o ‘carry the war into Africa’ by prosecuting that Company for injuring the business of others.