Green’s Dictionary of Slang

(usu. US black) one’s home, esp. among black speakers, the South.

1920		(con. WWI) Dos Passos One Man’s Initiation: 1917 (1969) 89: ‘I used to think that down home was the only place they knew how to live, but oh, boy . . .’ said Tom Randolph.
1928		C. McKay Home to Harlem 91: Zeddy was already at the Congo with a sweet, timid, satin-faced brown just from down home.
1952		L. Hughes Laughing to Keep from Crying 10: Well, I ain’t from no down home [...] I’m from the North.
1969		N. Cohn Awopbop. (1970) 127: ‘I don’t dig down-home any more,’ said one of the Four Tops. ‘It’s embarrassing.’.
1972		D. Claerbaut Black Jargon in White America 63: down homen. the South.