- Oct 3 7.8 earthquake shakes Pleasant Valley, Nevada
- Oct 4 Dinosaur National Monument in Colorado & Utah is established
- Oct 5 Allies land troops at the northern Greek city of Salonika; Greece is nominally neutral but allows the landing
- Oct 5 Bulgaria enters World War I as one of the Central Powers.
Edith Cavell Sentenced
Oct 7 English nurse Edith Cavell sentenced to death along with 34 others by German court martial for running underground network to free Allied soldiers
- Oct 8 Battle of Loos on WWI Western Front ends, German forces contain British attack (85,000 casualties)
- Oct 8 Phillies win their 1st & only World Series game before 1980, beating Red Sox, 3-1, with an 8th inning 2 run rally
- Oct 9 Belgrade, Serbia, surrenders to Central leaders
- Oct 9 Gil Anderson races auto (165.1 km record) in Sheepshead Bay, New York
- Oct 9 Louis Kaufmans comedy "Unchastened Woman" premieres in New York City
President Attends the World Series
Oct 9 Woodrow Wilson becomes first US President to attend a World Series game
- Oct 11 Bulgarian anti-Serbian offensive begins
- Oct 12 Despite international protest, Edith Cavell an English nurse in Belgium, is executed by the Germans for aiding the escape of Allied prisoners
Ford's Millionth Car
Oct 12 Ford Motor Company under Henry Ford manufactures its 1 millionth automobile at the River Rouge plant in Detroit
Hyphenated Americans
Oct 12 Theodore Roosevelt criticizes US citizens who identify themselves with dual nationalities
- Oct 13 Baseball World Series: Boston Red Sox beat Philadelphia Phillies, 5-4 at the Baker Bowl to clinch series 4-1
- Oct 16 Great Britain declares war on Bulgaria
- Oct 18 3rd Italian offensive at Isonzo
- Oct 19 Russia and Italy declare war on Bulgaria
- Oct 19 US bankers arrange a $500 million loan to the British and French
- Oct 21 1st transatlantic radiotelephone message, Arlington, Va to Paris
American Note to Britain
Oct 21 William Jennings Bryan's successor as US Secretary of State, Robert Lansing, sends a note to Britain protesting interference with US shipping
- Oct 23 1st national horseshoe throwing championship at Kellerton, Iowa
Women's Suffrage March on Fifth Ave, New York
Oct 23 An estimated 25,000 supporters in a women's suffrage march on New York's Fifth Ave, led by Dr. Anna Shaw and Carrie Chapman Catt, founder of the League of Women Voters
- Oct 25 James L Curtis named US Minister for Liberia
PM Billy Hughes
Oct 27 Andrew Fisher is replaced as Labour Prime Minister by William 'Billy' Hughes, who will advocate a more active role for Australians in the war
An Alpine Symphony
Oct 28 Richard Strauss' tone poem "Eine Alpensinfonie (An Alpine Symphony)" premieres in Berlin
Aristide Briand Returns
Oct 29 Aristide Briand becomes Prime Minister of France for the 3rd time
Admirals
Aviators
Gangsters
Generals
Industrialists
Suffragists