What are some of the key events that shaped American literature since 1915?

Early 20th C

End of railroad era, beginning of the automotive era

Ford’s mass-produced cars were cheap enough that even blue-collar workers could afford them. What were once small, isolated urban communities were slowly being connected by highways – but big engineering projects were expensive and didn’t seem sensible, since most people lived near trains.

1902 – First Rose Bowl game
1903 – Movie, The Great Train Robbery (first movie that told a story)
1903 – Ford Motor Company founded
1903 – Wright Brothers’ first powered human flight
1904 – Teddy Roosevelt acquires land for Panama Canal
1908 – FBI founded
1909 – American Robert Perry reaches South Pole
1909 – NAACP (founded by WEB DuBois)
1910 – Boy Scouts of America
1912 – Titanic sinks
1914 – Europe at war (the US declares neutrality)
1917 – US enters The Great War
1919 to 1933: Prohibition
1920 – 19th Amendment
1020 - Flappers -- Jazz
1925 – Scopes trial
1927 – Lindbergh’s Spirit of St. Louis crosses Atlantic
1927 – First “talking picture” – The Jazz Singer. (Singing and music presented througha synchronized sound track; yet the filmmakers still used title cards to represent the spoken word within the film.
1928 – Mickey Mouse appears in Steamboat Willie
1929 – Roaring Twenties ends as the stock market crashes.

[My main source was Wikipedia, but these facts all count as general knoweldge.]