- October 20, 1382 “St. Mary’s College is founded at Westminster, England.”
- October 20, 1600 Battle of Sekigahara sets Tokugawa clan as Japan’s rulers (shoguns)
- October 20, 1740 “Maria Theresa became ruler of Austria, Hungary & Bohemia”
- October 20, 1740 “Maria Theresa takes the throne of Austria. France, Prussia, Bavaria and Saxony refuse to honour the Pragmatic Sanction and the War of the Austrian Succession begins.”
- October 20, 1781 “Patent of Toleration, providing limited freedom of worship, was approved in Habsburg Monarchy.”
- October 20, 1803 US Senate ratifies the Louisiana Purchase
- October 20, 1813 German Kingdom of Westphalia abolished
- October 20, 1817 First Mississippi showboat leaves Nashville on maiden voyage
- October 20, 1818 49th parallel established as the border between US & Canada
- October 20, 1818 “The Convention of 1818 signed between the United States and the United Kingdom which, among other things, settled the US-Canada border on the 49th parallel for most of its length.”
- October 20, 1818 US & Britain agree to joint control of Oregon country
- October 20, 1824 William H. Seward and Frances Adeline Miller Seward wed.
- October 20, 1827 “Battle of Navarino – a combined Turkish and Egyptian armada is destroyed by an allied British, French, and Russian naval force in the port of Navarino in Pylos, Greece. The most important result of this battle is the end of the Greek Liberation War and the affirmation of independence of modern Greece.”
- October 20, 1847 Little William Nelman poisons his grandfather
- October 20, 1883 “Peru and Chile signed the Treaty of Ancn, by which the Tarapac province was ceded to the latter, bringing an end to Peru’s involvement in the War of the Pacific.”
- October 20, 1883 “Treaty of Ancon, Peru cedes Tarapaca to Chile”
- October 20, 1890 Pike’s Peak railroad completed.
- October 20, 1891 First International 6 day bike race begins in New York
- October 20, 1898 NC Mutual & Provident Insurance Company forms
- October 20, 1903 US wins disputed boundary between the District of Alaska & Canada
- October 20, 1905 Great General Strike in Russia begins; lasts 11 days
- October 20, 1906 Dr Lee DeForest demonstrates his radio tube
- October 20, 1910 “The hull of the RMS Olympic, sister-ship to the ill-fated RMS Titanic, is launched from the Harland and Wolff shipyard in Belfast, Ireland.”
- October 20, 1911 Amundsen sets out on race to South Pole
- October 20, 1929 Bayshore Highway opens in San Francisco
- October 20, 1930 British White Paper restricts Jews from buying Arab land
- October 20, 1935 The Long March ends
- October 20, 1941 World War II: Thousands of civilians in Kragujevac in German-occupied Serbia are killed in the Kragujevac massacre.
- October 20, 1944 30 blocks of Cleveland Ohio burn after a liquid gas factory explodes
- October 20, 1944 “Liquid natural gas leaks from storage tanks in Cleveland, then explodes; the explosion and resulting fire level 30 blocks and kill 130.”
- October 20, 1944 Revolution by workers & students in Guatemala
- October 20, 1944 “The Soviet army and Yugoslav Partisans liberate Belgrade, the capital of Yugoslavia”
- October 20, 1947 HUAC opens hearings into alleged Communist influence in Hollywood
- October 20, 1951 “The “”Johnny Bright Incident”” occurred in Stillwater, Oklahoma”
- October 20, 1952 “Governor Evelyn Baring declared a state of emergency in Kenya and began arresting hundreds of suspected leaders of the Mau Mau Uprising, including Jomo Kenyatta, the future first President of Kenya.”
- October 20, 1955 Day-O is released by Harry Belafonte. It was later renamed to The Banana Boat Song.
- October 20, 1955 “Publication of The Return of the King, being the last part of The Lord of the Rings.”
- October 20, 1956 Hannes Lindemann begins journey across Atlantic in a 17 foot craft
- October 20, 1960 “First fully mechanized post office opened, Providence, RI”
- October 20, 1960 Number one hit on UK music charts – Roy Orbison – Only The Lonely