The terms black Liverpool and black America, no less than the African diaspora, refer to racialized geographies of the imagination. The mapping of racial signifiers onto geographical ones lends such terms the illusion of referring to physical rather than social locations. That there is no actual space that one could call "the African diaspora," despite how commonly it is mapped onto particular locales, points attention to the ways that social spaces are constructed in tandem with processes of racial formation.
Inspired by Paul Gilroy's first book, There Ain't No Black in the Union Jack: The Cultural Politics of Race and Nation (1987), I set out in 1991 to study the meanings and practices surrounding "race" and nation in Liverpool, England. Set in a city with one of the longest-settled black populations in the United Kingdom, my research investigated why and how black identity is constituted as the mutual opposite of English and British identities. Yet in pursuing these themes, I became increasingly amazed at how frequently my informants would make discursive forays into "black America." Nested at key moments in their narratives were references to the formative influence that black America—in many forms—has had on racial identity and politics in their city. The experiences they narrated were varied, and the narratives themselves were rich, poignant, and deeply gendered (p. 291).
From: Brown, Jacqueline Nassy. "Black Liverpool, Black America, and the Gendering of Diasporic Space." Cultural Anthropology 13.3 (1998): 291-325.