Green’s Dictionary of Slang

1. (US) in pl., the prosperous parts of a town, where the wealthy élite live [the way in which the wealthy gravitated to the higher ground in an era when the lowlands, usu. near the river, had a higher incidence of disease].

1966–68

in DARE.

2. (US black) the northern, often black, area of a city.

1972

D. Claerbaut Black Jargon in White America 68: highland n. the north side of the city, often where the black community is.