- Jan 1 Godert van der Capellen resigns as governor of Dutch-Indies
- Jan 30 The Menai Suspension Bridge connecting the Isle of Anglesey to the northwest coast of Wales opens, considered the world's first modern suspension bridge
- Feb 11 University College London founded; known until 1836 as London University
- Feb 13 American Temperance Society forms in Boston
- Feb 24 The signing of the Treaty of Yandaboo marks the end of the First Burmese War
- Feb 28 Biela's Comet rediscovered by Austrian astronomer Wilhelm von Biela (originally discovered 1772)
- Mar 4 1st US railroad chartered, Granite Railway in Quincy, Massachusetts
- Mar 14 General Congress of South American States assembles at Panama
Internal-Combustion Engine
Apr 1 Samuel Morey is issued the first U.S. patent for an internal-combustion engine, which he calls a “Gas or Vapour Engine"
- Apr 10 10,500 inhabitants of the Greek town Messolonghi start leaving the town after a year's siege by Turkish forces. Very few of them survive.
- Apr 12 Weber's opera "Oberon" premieres in London
- Apr 23 Missolonghi, Greece captured by Turks
- May 22 HMS Beagle departs on its first voyage to survey Patagonia and Tierra del Fuego
Jefferson and Adams Die the Same Day
Jul 4 Past presidents Thomas Jefferson and John Adams both die on the 50th anniversary of the Declaration of Independence, President John Quincy Adams calls "visible and palpable remarks of Divine Favor"
- Jul 26 Riots in Vilnius, Lithuania cause the death of many Jews
- Jul 30 Java prince Dipo Negoro surprise attacks Dutch colony, 82 killed
- Aug 18 Scottish explorer Alexander Gordon Laing travelling across the Sahara, is the first European to reach the fabled trading city of Timbuktu (murdered near there a few weeks later)
- Aug 19 Canada Co. chartered to colonize Upper Canada (Ontario)
- Aug 22 Colonies under Jedediah Strong Smith move near Salt Lake Utah
- Aug 24 Netherlands' South Willems Port (Bosch-Liege) opens
- Sep 3 USS Vincennes leaves NY to become 1st warship to circumnavigate globe
- Oct 7 Granite Railway (1st chartered railway in US) begins operations
- Nov 15 Dutch Business Me gets monopoly on opium trade in Java/Madura
- Nov 25 The Greek frigate Hellas arrives in Nafplion to become the first flagship of the Hellenic Navy
- Nov 27 John Walker invents friction match in England
- Dec 16 Benjamin W. Edwards rides into Mexican controlled Nacogdoches, Texas and declares himself ruler of the Republic of Fredonia.
Admirals
Aviators
Gangsters
Generals
Industrialists
Suffragists