- Jan 1 Holland Brigade under Brigadier-General David Hendrik Chassé reaches Madrid (Napoleonic Wars)
- Jan 5 Treaty of Dardanelles concluded between Britain & France
Historic Event
Jan 6 Napoleonic Wars: Invasion of Cayenne, by combined British, Portuguese and colonial Brazilian forces, begins
- Jan 12 British take Cayenne (French Guiana) from French (until 1814)
- Jan 16 Peninsular War: The British defeat the French at the Battle of Corunna
- Jan 20 1st US geology book published by William Maclure
- Feb 1 Dutch King Louis Napoleon accepts metric system
- Feb 3 Territory of Illinois organizes (including present-day Wisconsin)
- Feb 8 Franz I of Austria declares war on France
Historic Invention
Feb 11 Robert Fulton patents steamboat
President Inaugurated
Mar 4 James Madison becomes 1st US President inaugurated in American-made clothes
- Mar 22 Charles XIII succeeds Gustav IV Adolf to the Swedish throne
- Mar 28 Peninsular War: France defeats Spain in the Battle of Medelin
- Mar 29 King Gustav IV Adolf of Sweden abdicates after a coup d'état. At the Diet of Porvoo, Finland's four Estates pledge allegiance to Alexander I of Russia, commencing the secession of the Grand Duchy of Finland from Sweden.
- Apr 18 First run of 2,000 guineas horse race at Newmarket, England
- Apr 20 Napoleon I and French forces defeat Austria at Battle of Abensberg, Bavaria
- Apr 22 Battle at Eckmuhl - Napoleon beats Austria Archduke Charles
- May 2 Dartmoor Prison in England opens to house French prisoners of war
- May 5 Citizenship is denied to Jews of Aargau Canton, Switzerland
- May 5 Mary Kies is 1st woman issued a US patent for weaving straw
- May 17 Papal States annexed by France
- May 21 Battle of Aspern-Essling: Austrian archduke Charles beats Napoleon and his army. Napoleon's first defeat in 10 years.
- Jun 1 Allardyce Barclay begins a bet of walking 1 mile every hour for 1,000 hours. Each hour he walked a mile round trip from his home
- Jun 6 Sweden declares independence, constitutional monarchy established with a new constitution empowering Riksdag after 20 years of absolute monarchy
- Jun 8 William Hyde Wollaston invents the first reflective goniometer
- Jun 10 1st US steamboat to a make an ocean voyage leaves NY for Philadelphia
- Jul 5 -6) Battle of Wagram - Napoleon beats archduke Charles
- Jul 16 La Paz, Bolivia declares its independence from the Spanish Crown and forms the Junta Tuitiva led by Pedro Domingo Murillo, the 1st independent government in Spanish America
- Jul 27 Battle of Talavera: British/Spanish army vs French army
- Jul 30 British armed force of 39,000 lands in Walcheren
- Jul 31 1st practical US railroad track (wooden, for horse-drawn cars), Philadelphia
- Aug 8 70 disciples of Gaon of Vilnius, arrive in Palestine
- Aug 10 Area of Quinto is the first to declare itself independent of Spain in Latin America, though put down by the Spanish after 24 day (now Ecuador's National Day)
- Sep 17 Peace between Sweden and Russia in the Finnish War. The territory to become Finland is ceded to Russia by the Treaty of Fredrikshamn.
- Sep 18 Royal Opera House in London opens
Election of Interest
Oct 4 Spencer Perceval becomes Prime Minister of the United Kingdom after William Cavendish-Bentinck, Duke of Portland retires due to ill health
- Nov 22 Peregrine Williamson of Baltimore patents a steel pen
- Nov 27 Berners Street hoax: Theodore Hook bets he can make any address the most talked-about in London, proceeds to win by bringing London to a standstill
- Dec 25 Physician Ephraim McDowell performs the first abdominal surgery in the U.S, an ovariotomy to remove a 22 lb ovarian tumor
- Dec 26 British invasionary troop leaves Vlissingen
- Dec 30 Wearing masks at balls forbidden in Boston