Timeline of United States history (1900–29)

This section of the Timeline of United States history concerns events from 1900 to 1929.

U.S. territorial extent in 1900

1900s

• 1900 - U.S. population exceeds 75 million
• 1900 - U.S. helps put down Boxer Rebellion
• 1900 - 1900 Galveston hurricane
• 1901 - William McKinley assassinated
• 1901 - Theodore Roosevelt becomes President
• 1901 - U.S. Steel founded by John Pierpont Morgan
• 1901 - Hay–Pauncefote Treaty
• 1902 - Drago Doctrine
• 1902 - First Rose Bowl game played
• 1902 - Newlands Reclamation Act
• 1903 - Great Train Robbery movie opens

Motor Company created

• 1903 - Ford Motor Company formed
• 1903 - First World Series
• 1903 - Elkins Act
• 1903 - Big Stick Diplomacy
• 1903 - Hay–Bunau-Varilla Treaty
• 1903 - Hay–Herrán Treaty
• 1903 - Department of Commerce and Labor created
• 1903 - The Wright brothers make their first powered flight in the Wright Flyer
• 1904 - Roosevelt Corollary to Monroe Doctrine
• 1904 - Panama Canal Zone acquired
• 1904 - Worlds Fair St. Louis
• 1905 - Niagara Falls conference
• 1905 - Industrial Workers of the World
• 1906 - Susan B. Anthony dies
• 1906 - Algeciras Conference
• 1906 - Pure Food and Drug Act and Meat Inspection Act
• 1906 - Hepburn Act
• 1906 - Theodore Roosevelt negotiates Treaty of Portsmouth, receives Nobel Peace Prize

Teddy Roosevelt, the Bull Moose, led American progressives in the early 20th century

• 1906 - San Francisco earthquake
• 1907 - Oklahoma becomes a state
• 1907 - Gentlemen's Agreement
• 1907 - Coal mine explodes in Monongah, West Virginia, killing at least 361. Worst industrial accident in American history.
• 1908 - Ford Model T appears on market
• 1908 - Root–Takahira Agreement
• 1908 - Federal Bureau of Investigation established
• 1908 - Aldrich–Vreeland Act
• 1909 - The U.S. penny is changed to the Abraham Lincoln design
• 1909 - William Howard Taft becomes President
• 1909 - Robert Peary claims to have reached the North Pole
• 1909 - NAACP founded by W. E. B. Du Bois
• 1909 - Payne–Aldrich Tariff Act
• 1909 - Taft implements Dollar Diplomacy
• 1909 - Pinchot–Ballinger controversy

1910s

• 1910 - Mann–Elkins Act
• 1910 - Mann Act
• 1911 - Supreme Court breaks up Standard Oil
• 1911 - First ever Indianapolis 500 is staged; Ray Harroun is the first winner
• 1912 - RMS Titanic sinks
• 1912 - New Mexico and Arizona become states
• 1912 - Girl Scouts of the USA was started by Juliette Gordon Low
• 1912 - Theodore Roosevelt shot, but not killed, while campaigning for the Bull Moose Party
• 1913 - Woodrow Wilson becomes President
• 1913 - 16th Amendment, establishing an income tax
• 1913 - End of the Philippine–American War
• 1913 - The Armory Show opens in New York City introducing Modern art both American and European to the American public.
• 1913 - 17th Amendment, establishing direct election of U.S. Senators.
• 1913 - Underwood Tariff
• 1913 - Henry Ford develops the modern assembly line
• 1914 - Mother's Day established as a national holiday
• 1914 - Federal Trade Commission created
• 1914 - Clayton Antitrust Act
• 1914 - ABC Powers
• 1915 - The Birth of a Nation opens
• 1915 - RMS Lusitania sunk
• 1916 - U.S. acquires Virgin Islands
• 1916 - Jeannette Rankin first woman elected to U.S. congress
• 1916 - Louis Brandeis appointed to Supreme Court
• 1916 - Adamson Railway Labor Act
• 1916 - Federal Farm Loan Act
• 1916 - Jone Act
• 1917 - Zimmermann Telegram
• 1917 - U.S. enters World War I
• 1917 - Espionage and Sedition Acts
• 1917 - Lansing–Ishii Agreement
• 1917 - U.S. Virgin Islands purchased from Denmark
• 1917-1920 - First Red Scare, marked by a widespread fear of Bolshevism and anarchism
• 1918 - President Wilson's Fourteen Points, which assures citizens that the Great War was being fought for a moral cause and for postwar peace in Europe
• 1918 - Treaty of Versailles ends World War I
• 1919 - Theodore Roosevelt dies
• 1919 - United States Senate rejects Treaty of Versailles and League of Nations
• 1919 - 18th Amendment, establishing Prohibition
• 1919 - Black Sox Scandal during the that year's World Series, wherein the fallout lasts for decades

1920s

• 1920 - 19th Amendment, granting women the right to vote
• 1920 - Sacco and Vanzetti arrested
• 1920 - First radio broadcasts in Pittsburgh and Detroit
• 1920 - Volstead Act
• 1920 - Esch–Cummins Act
• 1920 - NFL
• 1921 - Warren G. Harding becomes President
• 1921 - Washington Disarmament Conference of 1921
• 1921 - Emergency Quota Act
• 1922 - Fordney–McCumber Tariff
• 1923 - President Warren G. Harding dies; Calvin Coolidge succeeds him
• 1923 - Teapot Dome scandal
• 1924 - Immigration Act Basic Law
• 1924 - J. Edgar Hoover is appointed director of the Bureau of Investigation — predecessor to the FBI.
• 1925 - Scopes Trial, whose outcome found that the teaching of evolution in the classroom "does not violate church and state or state religion laws but instead, merely prohibits the teaching of evolution on the grounds of intellectual disagreement"
• 1925 - Nellie Tayloe Ross elected governor of Wyoming
• 1925 - WSM broadcasts the Grand Ole Opry for the first time.
• 1926 - NBC founded as the U.S.'s first major broadcast network
• 1927 - Sacco and Vanzetti executed, seven years after they were convicted of murdering two men during an armed robbery in Massachusetts
• 1927 - Charles Lindbergh makes first trans-Atlantic flight
• 1927 - The Jazz Singer, the first "talkie" (motion picture with sound) is released
• 1927 - U.S. citizenship granted to inhabitants of U.S. Virgin Islands
• 1927 - Columbia Broadcasting System (later called CBS) becomes second national radio network in the U.S.
• 1928 - Disney's Steamboat Willie opens, the first animated picture to feature Mickey Mouse
• 1928 - Kellogg–Briand Pact
• 1928 - Amelia Earhart becomes the first woman to fly solo across the Atlantic Ocean.
• 1929 - Herbert Hoover becomes President
• 1929 - St. Valentine's Day Massacre
• 1929 - Immigration Act
• 1929 - The Dow Jones Industrial Average plummets a record 68 points over a two-day period, setting off the Wall Street Crash of 1929 and triggering the Great Depression
• 1929 - The Museum of Modern Art opens to the public in New York City
• 1929 - American Samoa officially becomes a U.S. territory
• 1929 - The Great Depression Starts