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1801 (MDCCCI) was a common year starting on Thursday of the Gregorian calendar and a common year starting on Tuesday of the Julian calendar, the 1801st year of the Common Era (CE) and Anno Domini (AD) designations, the 801st year of the 2nd millennium, the 1st year of the 19th century, and the 2nd year of the 1800s decade. As of the start of 1801, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.
- January 1
- January 3 – Toussaint Louverture triumphantly enters Santo Domingo, the capital of the former Spanish colony of Santo Domingo, which has become a colony of Napoleonic France.
- January 31 – John Marshall is appointed Chief Justice of the United States.
- February 4 – William Pitt the Younger resigns as Prime Minister of the United Kingdom.
- February 9 – The Treaty of Lunéville ends the War of the Second Coalition between France and Austria. Under the terms of the treaty, Aachen is officially annexed by France.
- February 17 – An electoral tie between Thomas Jefferson and Aaron Burr is resolved, when Jefferson is elected President of the United States and Burr Vice President by the United States House of Representatives.
- February 27 – Washington, D.C. is placed under the jurisdiction of the United States Congress.
- March 4 – Thomas Jefferson is sworn in as the third President of the United States.
- March 10 – The first census is held in Great Britain. The population of England and Wales is determined to be 8.9 million, with London revealed to have 860,035 residents. 1.5 million people live in cities of 20,000 or more in England and Wales, accounting for 17% of the total English population.
- March 14 – Henry Addington becomes First Lord of the Treasury and Chancellor of the Exchequer, effectively Prime Minister of the United Kingdom.
- March 21 – Second Battle of Abukir in Egypt: British troops defeat the French, but the British commander, Sir Ralph Abercromby, dies later of a wound received in the action.
- March 23 – Tsar Paul I of Russia is murdered; he is succeeded by his son Alexander I.
- January 3 – Gijsbert Haan, Dutch-American religious leader (d. 1874)
- January 11 – Honório Hermeto Carneiro Leão, Marquis of Paraná, Brazilian politician (d. 1856)
- January 14 – Jane Welsh Carlyle, wife of Scottish essayist Thomas Carlyle (d. 1866)
- February 1
- February 13 – János Kardos, Hungarian Slovenes evangelical priest, teacher and writer (d. 1875)
- February 21 – John Henry Newman, English Catholic Cardinal (d. 1890)
- May 5 – Pío Pico, last Governor of Alta California (d. 1894)
- May 9 – Peter Hesketh-Fleetwood, English Member of Parliament, developer (d. 1866)
- May 11 – Henri Labrouste, French architect (d. 1875)
- May 16 – William H. Seward, 24th United States Secretary of State (d. 1872)
- May 17 – Lovisa Åhrberg, first woman doctor, surgeon in Sweden (d. 1881)
- May 31 – Johann Georg Baiter, Swiss philologist, textual critic (d. 1877)
- June 1 – Brigham Young, American Mormon leader, colonizer (d. 1877)
- June 4 – James Pennethorne, English architect (d. 1871)
- June 14 – Heber C. Kimball, American religious leader (d. 1868)
- June 16 – Julius Plücker, German mathematician, physicist (d. 1868)
- June 30 – Frédéric Bastiat, French philosopher (d. 1850)
- July 5 – David Farragut, American admiral (d. 1870)
- July 14 – Johannes Peter Müller, German physiologist, comparative anatomist, ichthyologist, and herpetologist (d. 1858)
- July 27 – George Biddell Airy, English mathematician, astronomer (d. 1892)
- September 1 – Hortense Allart, French writer (d. 1879)
- September 3 – Christian Erich Hermann von Meyer, German palaeontologist (d. 1869)
- October 12
- October 23 – Albert Lortzing, German composer (d. 1851)
- November 3
- November 10 – Vladimir Dal, Russian lexicographer (d. 1872)
- November 13 – Queen Elisabeth Ludovika of Bavaria, queen of Prussia (d. 1873)
- December 11 – Christian Dietrich Grabbe, German writer (d. 1836)
- January 2 – Johann Kaspar Lavater, Swiss physiognomist (b. 1741)
- February 7 – Daniel Chodowiecki, Polish painter (b. 1726)
- March 14 – Margarita "Peggy" Schuyler Van Rensselaer, American socialite, Angelica Schuyler Church's sister (b. 1758)
- March 19 – Ambrosio O'Higgins, 1st Marquis of Osorno, Spanish viceroy of Peru and Governor of the Captaincy General of Chile, father of Bernardo O'Higgins
- March 21 – Andrea Luchesi, Italian composer (b. 1741)
- March 23 – Tsar Paul I of Russia (b. 1754)
- March 25 – Novalis, German poet (b. 1772)
- March 28 – Ralph Abercromby, British general (b. 1734)
- April 2 – Thomas Dadford, Jr., British engineer
- April 7 – Noël François de Wailly, French lexicographer (b. 1724)
- May 17 – William Heberden, English physician (b. 1710)
- June 4 – Frederick Muhlenberg, first Speaker of the U.S. House of Representatives (b. 1750)
- June 14 – Benedict Arnold, American Revolution hero, then traitor (b. 1741)
- September 19 – Johann Gottfried Koehler, German astronomer (b. 1745)
- October 3 – Philippe Henri, marquis de Ségur, Marshal of France (b. 1724)
- November 4 – William Shippen, American physician, Continental Congressman (b. 1712)
- November 5 – Motoori Norinaga, Japanese philologist, scholar (b. 1730)
- November 24 – Franz Moritz von Lacy, Austrian field marshal (b. 1725)
- November 24 – Philip Hamilton, son of American soldier and statesman, Alexander Hamilton (b. 1782)
- Date unknown – Ulrica Arfvidsson, Swedish fortune teller (b. 1734)
- ^ "Chronology of State Medicine". Archived from the original on August 9, 2007. Retrieved 2007-08-10.
- ^ Everett, Jason M., ed. (2006). "1801". The People's Chronology. Thomson Gale.
- ^ "Dreadful events in the front rows of the ring at Madrid and the death of the mayor of Torrejón, Plate 21 of La Tauromaquia". National Galleries of Scotland. Retrieved on 25 February 2010.
- ^ Michael P. Fitzsimmons, From Artisan to Worker: Guilds, the French State, and the Organization of Labor, 1776-1821 (Cambridge University Press, 2010) p132
- ^ British Steam. Igloo Books. 2016. pp. 10–13.
- ^ Foucault, Michel (1961). Folie et déraison: histoire de la folie à l'âge classique.