Despite the fact that African-Americans did not serve in large numbers in the First World War, the war offered some opportunities to work in northern industrial cities. For this reason, thousands of African-Americans, seeking economic opportunity as well as escape from the brutality of Jim Crow, moved northward in what has become known as the Great Migration. The result was the creation of large African-American communities in northern cities.
One reason why African-Americans continued to come to the North after World War I was the decline in immigration caused by the imposition of harsh new quotas in the 1920s that discriminated against Eastern and Southern Europeans. These quotas were part of an overall backlash against immigrants. While enormous numbers of immigrants fought in the war, immigrant communities were generally suspect, especially after the Russian Revolution. Many Americans associated Eastern and Southern European immigrants with political radicalism, and so supported the immigration restrictions. These restrictions, however, did not apply to Mexican-Americans, though later restrictions did.
Finally, many women found limited economic opportunities during the war, taking advantage of the tight labor market created by the war. But the most important consequence of the war for women was the passage of the Nineteenth Amendment, which protected suffrage for women throughout the country. During the war, suffrage advocates had supported the war and pointedly argued that President Wilson's arguments about democracy abroad should also be applied to women's rights at home.