Green’s Dictionary of Slang

Sugar Hill n.

[note Lincoln U. (Oxford, Penn.) use c.1934: ‘Sugar Hill. The newest dormitory, where rentals and appointments are relatively high]
(US black)

1. [1920s–40s] that area of Harlem otherwise known as Coogan’s Bluff, between Amsterdam and Edgecombe Avenues, between 138th and 155th Streets. As well as the rich, many black intellectuals and artists chose to live in the area, known for its grand apartment houses, once the original white population had moved out during the 1920s; thus Sugar Hiller, a resident of this area, thus attrib [sugar n.1 (1)].

2. [1930s–50s] the brothel and ‘red-light’ area of the black part of any southern town [sugar n.4 (1)].