By what year did the area around 140th street and 7th Avenue become populated primarily by African American?

By the 1930s, the area around 140th Street and 7th Avenue in Harlem became predominantly populated by African Americans. This demographic shift was largely driven by the Great Migration, where many African Americans moved from the rural South to urban areas in the North in search of better opportunities and living conditions. Harlem emerged as a cultural hub during this period, contributing significantly to the Harlem Renaissance.