After which significant event did a large number of African Americans migrate to northern cities in search of jobs?

The migration of a large number of African Americans to northern cities in search of jobs is most closely associated with World War I. This period marked the beginning of what is known as the Great Migration, during which African Americans moved from the rural South to industrialized northern cities like Chicago, Detroit, and New York.

The Great Migration was fueled by multiple factors, including the desire to escape the oppressive Jim Crow laws in the South and to seek better economic opportunities in the burgeoning defense industries of the North, which were experiencing labor shortages due to the war effort. While World War II also prompted another wave of migration, the significant move began during World War I as African Americans sought to fill jobs left vacant by men going off to war and also pursued the promise of greater social and economic freedom in northern urban areas.

Understanding this context highlights the social and economic dynamics of the time, illustrating how historical events can shape demographic changes and contribute to the development of communities.