October 26 is the 299th day of the year (300th in leap years) in the Gregorian calendar. There are 66 days remaining until the end of the year.
* 306 – Martyrdom of Saint Demetrius of Thessaloniki
* 1597 – Imjin War: Admiral Yi Sun-sin routs the Japanese Navy of 300 ships with only 13 ships at the Battle of Myeongnyang.
* 1640 – The Treaty of Ripon is signed, restoring peace between Scotland and Charles I of England.
* 1689 – General Piccolomini of Austria burned down Skopje to prevent the spread of cholera. He died of cholera himself soon after.
* 1774 – The first Continental Congress adjourns in Philadelphia, Pennsylvania.
* 1775 – King George III goes before Parliament to declare the American colonies in rebellion, and authorized a military response to quell the American Revolution.
* 1776 – Benjamin Franklin departs from America for France on a mission to seek French support for the American Revolution.
* 1795 – The French Directory, a five-man revolutionary government, is created.
* 1811 – The Argentine government declare the freedom of expression for the press by decree.
* 1825 – The Erie Canal opens – passage from Albany, New York to Lake Erie.
* 1859 – The Royal Charter is wrecked on the coast of Anglesey, north Wales with 459 dead.
* 1860 – Meeting of Teano. Giuseppe Garibaldi, conqueror of the Kingdom of Two Sicilies, gives it to King Victor Emmanuel II of Italy.
* 1861 – The Pony Express officially ceased operations.
* 1881 – The Gunfight at the O.K. Corral takes place at Tombstone, Arizona.
* 1905 – Norway becomes independent from Sweden.
* 1909 – Itō Hirobumi, Resident-General of Korea, was shot to death by Korean independence supporter Ahn Jung-geun at the Harbin train station in Manchuria.
* 1912 – First Balkan War: The capital city of Macedonia, Thessaloniki, is unified with Greece on the feast day of its patron Saint Demetrius. On the same day, Serbian troops captured Skopje.
* 1917 – World War I: Battle of Caporetto; Italy suffers a catastrophic defeat at the forces of Austria-Hungary and Germany. The young unknown Oberleutnant Erwin Rommel captures Mount Matajur with only 100 Germans against a force of over 7000 Italians.
* 1917 – World War I: Brazil declared in state of war with Central Powers.
* 1918 – Erich Ludendorff, quartermaster-general of the Imperial German Army, is dismissed by Kaiser Wilhelm II of Germany for refusing to cooperate in peace negotiations.
* 1921 – The Chicago Theatre opens.
* 1936 – The first electric generator at Hoover Dam goes into full operation.
* 1940 – The P-51 Mustang makes its maiden flight.
* 1942 – World War II: In the Battle of the Santa Cruz Islands during the Guadalcanal Campaign, one U.S. aircraft carrier, Hornet, is sunk and another aircraft carrier, Enterprise, is heavily damaged.
* 1943 – World War II: First flight of the Dornier Do 335 "Pfeil".
* 1944 – World War II: The Battle of Leyte Gulf ends with an overwhelming American victory.
* 1947 – The Maharaja of Kashmir agrees to allow his kingdom to join India.
* 1948 – Killer smog settles into Donora, Pennsylvania.
* 1955 – After the last Allied troops have left the country and following the provisions of the Austrian Independence Treaty, Austria declares permanent neutrality.
* 1955 – Ngô Đình Diệm declares himself Premier of South Vietnam.
* 1958 – Pan American Airways makes the first commercial flight of the Boeing 707 from New York City to Paris, France.
* 1959 – The world sees the far side of the Moon for the first time.
* 1964 – Eric Edgar Cooke becomes last person in Western Australia to be executed.
* 1967 – Mohammad Reza Pahlavi crowns himself Emperor of Iran and then crowns his wife Farah Empress of Iran.
* 1977 – The last natural case of smallpox is discovered in Merca district, Somalia. The WHO and the CDC consider this date the anniversary of the eradication of smallpox, the most spectacular success of vaccination.
* 1979 – Park Chung-hee, President of South Korea is assassinated by KCIA head Kim Jae-kyu. Choi Kyu-ha becomes the acting President; Kim is executed the following May.
* 1984 – "Baby Fae" receives a heart transplant from a baboon.
* 1985 – The Australian government returns ownership of Uluru to the local Pitjantjatjara Aborigines.
* 1992 – The Charlottetown Accord fails to win majority support in a Canada wide referendum.
* 1992 – The London Ambulance Service is thrown into chaos after the implementation of a new CAD, or Computer Aided Despatch, system which failed.
* 1994 – Jordan and Israel sign a peace treaty
* 1995 – Israeli-Palestinian Conflict: Mossad agents assassinate Islamic Jihad leader Fathi Shikaki in his hotel in Malta.
* 1999 – Britain's House of Lords votes to end the right of hereditary peers to vote in Britain's upper chamber of Parliament.
* 2000 – Laurent Gbagbo takes over as president of Côte d'Ivoire following a popular uprising against President Robert Guéï.
* 2001 – The United States passes the USA PATRIOT Act into law.
* 2002 – Moscow Theatre Siege: Approximately 50 Chechen terrorists and 150 hostages die when Russian Spetsnaz storm a theater building in Moscow, which had been occupied by the terrorists during a musical performance three days before.
* 2003 – The Cedar Fire, the second-largest fire in California history, kills 15 people, consumes 250,000 acres (1,000 km²), and destroys 2,200 homes around San Diego.