World War I was one of the major factors in the shift of the African American population from being largely rural before the war to largely urban afterward. By the time the war began, African Americans in the southern states had endured decades of Jim Crow laws, disenfranchisement, and the indignities of sharecropping. Most lived in poverty with no hope of upward mobility.
When the United States entered the war in 1917, the demand for workers in Northern factories increased. Many of the former factory workers were overseas fighting in the military, and the formerly steady supply of European immigrants who usually filled the factory jobs had dried up as a result of the conflict. Furthermore, there was an increased demand for production to support the war effort. With not enough employees to work the factories, many industry leaders began recruiting African Americans from the South.
During this decade, about half a million African Americans moved to northern cities in what became known as the Great Migration. This signaled a shift in the overall African American experience from being largely rural and agrarian to being increasingly urban and industrial. In the cities, most still faced significant discrimination. Cities were largely segregated, though seldom through any official Jim Crow–like laws. Many African Americans lived in crowded and unsanitary neighborhoods and worked low-wage jobs. However, they still found more freedom than they had in the South.
The Great Migration changed the face of America's northern cities. African Americans from the South brought their culture and traditions with them to the North. Their communities became known for what are now iconic cultural elements, characterized by music (particularly jazz and blues), cuisine, literature, and other arts. The Harlem Renaissance of the 1920s was a direct result of the Great Migration. Additionally, while they still faced prejudice and push-back from much of the white community, African Americans in Northern cities found ways to become politically, economically, and socially active in their new home, thus changing the fabric and identity of urban America.