| •1915 | Ku Klux Klan revived |
| •1917–1918 | Great migration begins |
| •1917 | Russian Revolution begins |
| •1918–1920 | Worldwide influenza epidemic |
| •1919 | 4 million workers go on strike nationwide |
| Race riots |
| Radicals mail bombs |
| Palmer raids begin |
| •1919–1929 | Harlem Renaissance |
| •1920 | American Civil Liberties Union (ACLU) formed |
| •1921 | J. Edgar Hoover becomes director of the Bureau of Investigation |
| Teapot Dome scandal |
| •1924 | Indian Citizens Act Passed |
| National Origins Act passed |
| Charles Dawes negotiates reduction in Germany's reparations payments |
| •1925–1929 | U.S. farm income drops by 50 percent |
| •1925 | Scopes trial |
| •1927 | Sacco and Vanzetti executed |
| •1928 | Democrat Al Smith loses presidential election to Republican Herbert Hoover |
| •1929 | Stock market crash sparks Great Depression |