1820

• January 1 – A constitutionalist military insurrection at Cádiz leads to the summoning of the Spanish Parliament to meet on March 7, becoming the nominal beginning of the "Trienio Liberal" in Spain.{{cite book|author=Miguel A López-Morell|title=The House of Rothschild in Spain, 1812–1941|url=https://books.google.com/books?id=XOYFgUAxnkIC&pg=PT46|date=28 June 2013|publisher=Ashgate Publishing, Ltd.|isbn=978-1-4724-0424-4|pages=46}}
• January 8 – The General Maritime Treaty of 1820 is signed between the sheikhs of Abu Dhabi, Sharjah, Ajman, Umm al-Quwain and Ras Al Khaimah (later constituents of the Trucial States) in the Arabian Peninsula and the United Kingdom.{{Cite book|last=Lorimer|first=John|title=Gazetteer of the Persian Gulf|publisher=British Government|location=Bombay|year=1915}}
• January 27 (NS, January 15 OS) – An Imperial Russian Navy expedition, led by Fabian Gottlieb von Bellingshausen in Vostok with Mikhail Petrovich Lazarev, sights the Antarctic ice sheet.{{cite book|first=A. G. E.|last=Jones|year=1982|title=Antarctica Observed: who discovered the Antarctic Continent?|publisher=Caedmon of Whitby|isbn=0-905355-25-3}}
• January 29 – George IV of the United Kingdom becomes the new British monarch upon the death his father King George III after 59 years on the throne. The elder George's death ends the 9-year period known as the British Regency.
• January 30 – British Royal Navy captain Edward Bransfield, an Irishman, becomes the first person to positively identify Antarctica as a land mass.
• February 6
• Capture of Valdivia: Lord Cochrane occupies Valdivia in the name of the Republic of Chile.
• A group of 86 free African American colonists sail from New York City to Freetown, Sierra Leone, with a goal of creating a home for freed American slaves, to be called "Liberia".
• February 14 – Emperor Minh Mạng starts to rule in Vietnam.
• February 20 – A revolt begins against the Spanish crown in Santa María Chiquimula (now in Guatemala).{{cite book|author=William George Lovell|title=Conquest and Survival in Colonial Guatemala: A Historical Geography of the Cuchumatán Highlands, 1500-1821|url=https://books.google.com/books?id=05wSqQiu52MC&pg=PA116|year=2005|publisher=McGill-Queen's Press - MQUP|isbn=978-0-7735-2741-6|pages=116}}
• February 23 – The Cato Street Conspiracy, a plot to assassinate Britain's Prime Minister, Lord Liverpool, and his Cabinet is thwarted when police in London arrest 13 plotters after being warned by an informant.{{cite book|author=Alexander Charles Ewald|title=The Last Century of Universal History: A Reference Book, Containing an Annotated Table of Chronology, Lists of Contemporary Sovereigns, a Dictionary of Battles and Sieges, and Biographical Notes of Eminent In-dividuals. From 1767 to 1867|url=https://books.google.com/books?id=flkQAAAAYAAJ&pg=PA67|year=1868|publisher=F. Warne & Company|pages=67}}
• March 3 – A fire in Guangzhou in China burns 15,000 houses and kills an undetermined number of people."Fires, Great", in The Insurance Cyclopeadia: Being an Historical Treasury of Events and Circumstances Connected with the Origin and Progress of Insurance, Cornelius Walford, ed. (C. and E. Layton, 1876) pp69
• March 3 and 6 – The Missouri Compromise becomes law, allowing admission of Missouri and Maine, slave and free states respectively, as U.S. states.
• March 9 – King Ferdinand VII of Spain accepts the new constitution, beginning the Trienio Liberal.
• March 10 – The Astronomical Society of London is founded.
• March 15 – Maine is admitted as the 23rd U.S. state.
• March 26 – Joseph Smith, founder of the Latter Day Saint movement, receives his First Vision in Palmyra, New York.Lefgren, J. C. (October 2002). "Oh, How Lovely Was the Morning: Sun 26 Mar 1820?". Meridian Magazine. (available at http://www.johnpratt.com/items/docs/lds/meridian/2002/vision.html)
• March 28 – An attempted coup d'état against Paraguayan dictator José Gaspar Rodríguez de Francia fails after a plot by Fulgencio Yegros and Pedro Juan Caballero.

• April 1 – A proclamation, signed "By order of the Committee of Organisation for forming a Provisional Government", begins the "Radical War" in Scotland.
• April 8 – The statue of the Venus de Milo (Aphrodite of Milos, {{Circa|150 BC}}-125 BC) is discovered on the Greek island of Milos, by a peasant named Yorgos Kentrotas.{{cite book|title=School Arts|url=https://books.google.com/books?id=18oVAQAAIAAJ|year=1922|publisher=Davis Publications|page=444}}
• April 12 – Alexander Ypsilantis becomes the leader of Filiki Eteria, a secret organization to overthrow Ottoman rule over Greece.
• April 15 – King William I of Württemberg marries his cousin, Pauline Therese, in Stuttgart.
• April – Hans Christian Ørsted discovers the relationship between electricity and magnetism.
• May 1 – The last judicial decapitation in the United Kingdom is meted out to the principals in the Cato Street conspirators after their public hanging for treason in London. Legally, the post-hanging beheading is a mitigation of the last sentence in Britain of "hanging, drawing and quartering".{{cite book|last=Abbott|first=Geoffrey|title=Execution: a Guide to the Ultimate Penalty|publisher=Summersdale Publishers|location=Chichester|year=2005|orig-date=1994|isbn=978-1-84024-433-5|pages=161–2}}
• May 11 – {{HMS|Beagle}}, the ship that will later take young Charles Darwin on his scientific voyage to examine the "origin of the species", is launched at Woolwich Dockyard.
• May 20 – At age 14, John Stuart Mill sets out on his formative trip to the south of France, staying with Samuel Bentham.
• June 5 – Caroline of Brunswick, the estranged wife of King George IV of the United Kingdom, returns to England after six years abroad in Italy, where she has been carrying on an affair. Since ascending the throne in January, the King had sought to receive his government's approval for a divorce.{{cite book|authorlink=Christopher Hibbert|first=Christopher|last=Hibbert|title=Wellington: A Personal History|publisher=Da Capo Press|year=1999|page=220}}
• June 12
• Élie Decazes, leader of the opposition in France's Chamber of Deputies, introduces the "Law of the Double Vote", a proposal to add to the existing legislators by creating 172 seats that would be "selected by special electoral colleges" made up of the wealthiest 25% of voters in each of France's departments.Munro Price, The Perilous Crown: France Between Revolutions, 1814-1848 (Pan Macmillan, 2010) p108
• Delegates in St. Louis in the Missouri Territory approve a proposed state constitution, proclaiming that they "do mutually agree to form and establish a free and independent republic, by the name of 'The State of Missouri'.""Missouri", in Constitutional Documents of the United States of America 1776-1860, ed. by Horst Dippel (K. G. Saur, 2007) p221
• June 29 – The cause of action that will lead to the U.S. Supreme Court case known as The Antelope arises, when a U.S. Treasury cutter captures a ship of the same name, which is transporting 281 Africans who had been captured as slaves, in violation of the U.S. law prohibiting the slave trade."Antelope Case", by John T. Noonan, Jr., in Dictionary of Afro-American Slavery, (Greenwood, 1997) p66

• July 13 – A revolt under Guglielmo Pepe forces Ferdinand I of the Two Sicilies to sign a constitution modeled on the Spanish Constitution of 1812.
• July 20 – Saint Cronan's Boys' National School opens in Bray, County Wicklow, Ireland under the title Bray Male School. Its notable pupils will include President of Ireland Cearbhall Ó Dálaigh.
• July 26 – Union Chain Bridge opens across the River Tweed, between England and Scotland. Its span of 449 ft (137 m) is the world's longest for a vehicular bridge at this time.{{cite book|url=https://archive.org/details/amemoirsuspensi01drewgoog|title=A Memoir of Suspension Bridges: Comprising The History Of Their Origin And Progress|chapter=Section III|last=Drewry|first=Charles Stewart|year=1832|publisher=Longman, Rees, Orme, Brown, Green & Longman|location=London|pages=[https://archive.org/details/amemoirsuspensi01drewgoog/page/n55 37]–41|access-date=August 16, 2011}}
• August 1 — The Regent's Canal through to the London Docks is opened.
• August 24 – A Constitutionalist insurrection breaks out at Oporto, Portugal.
• September 2 – The Daoguang Emperor succeeds to the throne of Qing dynasty China.
• September 5 – José Gervasio Artigas flees to Paraguay.
• September 15 – Revolution breaks out in Lisbon against John VI of Portugal.{{cite book |author1=Matthew Anthony Fitzsimons |url=https://books.google.com/books?id=h6IwAQAAIAAJ |title=The Catholic Church Today: Western Europe |author2=Jean Bécarud |publisher=University of Notre Dame Press |year=1969 |isbn=978-0-268-00307-4 |page=162}}

File:Chicago in 1820.jpg in 1820]]

• October 9 – Guayaquil declares independence from Spain.
• October 25–November 20 – The Congress of Troppau is convened between the rulers of Russia, Austria and Prussia.{{cite book|author=Paul W. Schroeder|title=Metternich's Diplomacy at its Zenith, 1820-1823: Austria and the Congresses of Troppau, Laibach, and Verona|url=https://books.google.com/books?id=GSbFDQAAQBAJ&pg=PA98|date=1 January 1962|publisher=University of Texas Press|isbn=978-0-292-75034-0|pages=98}}
• November 17 – American seal hunter Captain Nathaniel Palmer becomes the third known explorer to sight Antarctica. The Palmer Peninsula is later named after him.{{cite book|title=Oversight Visit to the Southern Pacific Rim: Report to the Committee on Science, Space, and Technology, U.S. House of Representatives, One Hundred First Congress, Second Session|url=https://books.google.com/books?id=0R151CAlW20C&pg=PA11|year=1991|publisher=U.S. Government Printing Office|pages=11}}
• November 20 – After the sinking of the American whaleship Essex of Nantucket, by a sperm whale in the southern Pacific Ocean, the survivors are left afloat in three small whaleboats. They eventually resort, by common consent, to cannibalism to allow some to survive.
• December 3 – James Monroe is re-elected, virtually unopposed, in the 1820 United States presidential election. One elector, William Plumer of New Hampshire, casts his vote for John Quincy Adams in order to protest the administration of Monroe and Daniel Tompkins while also establishing Adams as a contender for the election in 1824.Lynn W. Turner, “The Electoral Vote against Monroe in 1820-An American Legend,” The Mississippi Valley Historical Review 42, no. 2 (September 1955): 253-254, https://www.jstor.org/stable/1897643?seq=1.

• The Argentine Confederation (Argentina) formally claims the Falkland Islands, which are without permanent population at this time.{{cite book|title=The South Atlantic Crisis: Background, Consequences, Documentation : August 1982|url=https://books.google.com/books?id=c27jAAAAMAAJ&pg=PP4|year=1982|publisher=U.S. Department of State, Bureau of Public Affairs, Office of Public Communication, Editorial Division|pages=4}}
• Mount Rainier erupts over modern-day Seattle.
• 18,957 black slaves leave Luanda, Angola.
• Construction work is completed on the Citadelle Laferrière in Haiti, the largest fortification in the Americas, built on the orders of Henri Christophe to defend the country against potential French reoccupation.{{cite book|first=Michele|last=Wagner|title=Haiti|url=https://books.google.com/books?id=SWk1urXDuikC|year=2002|publisher=G. Stevens|isbn=978-0-8368-2351-6|page=53}}
• Anchor coinage is first struck in silver in London denominated in fractions of the Mauritian dollar for use in British colonies.

File:William-Tecumseh-Sherman.jpg]]

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• January 10 – Louisa Lane Drew, actress, prominent theater manager, grandmother of the Barrymores (d. 1897)
• January 17 – Anne Brontë, English author (d. 1849){{cite web |title=Anne Brontë {{!}} British author |url=https://www.britannica.com/biography/Anne-Bronte |website=Encyclopedia Britannica |access-date=April 17, 2019 |language=en}}
• January 20 – Alexandre-Émile Béguyer de Chancourtois, French chemist and mineralogist (d. 1886)
• January 30 – Concepción Arenal, Spanish feminist writer, activist (d. 1893){{cite book|title=Calendar of Spanish Anniversaries|url=https://books.google.com/books?id=vrYUAQAAIAAJ|year=1935|publisher=Tardy publishing Company, Incorporated}}
• February 8 – William Tecumseh Sherman, American Civil War general (d. 1891){{cite book|author=William Tecumseh Sherman|title=Memoirs of Gen. William T. Sherman: By Himself. To which are Added Chapters Completing His Life and Including His Funeral Obsequies by W. Fletcher Johnson and Carefully Reviewed by Major-General O. O. Howard|url=https://books.google.com/books?id=c9w4AQAAMAAJ&pg=PA438|year=1891|publisher=D. Appleton|pages=438–}}
• February 13 – James Geiss, English businessman (d. 1878)
• February 15
• Susan B. Anthony, American suffragist (d. 1906){{cite book|author=United States. Congress|title=Congressional Record: Proceedings and Debates of the ... Congress|url=https://books.google.com/books?id=zT-J4Y9mt3sC&pg=PA3217|year=1966|publisher=U.S. Government Printing Office|pages=3217}}
• Arvid Posse, 2nd Prime Minister of Sweden (d. 1901){{cite book|author1=Frank Moore Colby|author2=Harry Thurston Peck|title=The International Year Book|url=https://books.google.com/books?id=9k1MAAAAMAAJ|year=1902|publisher=Dodd, Mead|page=646}}
• February 17 – Henri Vieuxtemps, Belgian violinist and composer (d. 1881){{cite book|title=The Musical Monitor|url=https://books.google.com/books?id=DnpFAQAAMAAJ|year=1918|publisher=Mrs. David Allen Campbell|page=620}}
• February 28 – John Tenniel, English illustrator (d. 1914){{cite book|title=Sir John Tenniel|url=https://books.google.com/books?id=AnoKcQVWj3cC|year=1914|publisher=Bradbury, Agnew & Company|page=1863}}
• March 2 – Eduard Douwes Dekker, Dutch writer (d. 1887){{cite book|author=Multatuli|title=Max Havelaar, Or, The Coffee Auctions of the Dutch Trading Company|url=https://books.google.com/books?id=vvY2AAAAIAAJ|year=1982|publisher=University of Massachusetts Press|page=339|isbn=9780870233609 }}
• March 3 – Henry D. Cogswell, American temperance movement pioneer who endowed a number of Cogswell fountains (d. 1900)
• March 4 – Francesco Bentivegna, Italian revolutionary (d. 1856)
• March 4 – Alexander Worthy Clerk, Jamaican Moravian teacher and missionary (d. 1906)
• March 9 – Samuel Blatchford, Associate Justice of the Supreme Court of the United States (d. 1893)
• March 14 – Victor Emmanuel II of Italy (d. 1878){{cite book|title=The Statesman's Year-book|url=https://books.google.com/books?id=DawRAAAAYAAJ&pg=PA323|year=1867|publisher=Palgrave|pages=323}}
• March 17 – Martin Jenkins Crawford, American politician (d. 1883)
• March 20 – Alexandru Ioan Cuza, Romania's first reigning Domnitor (d. 1873){{cite book|title=Southeastern Europe: L'Europe Du Sud-Est|url=https://books.google.com/books?id=qUFpAAAAMAAJ|year=1974|publisher=Arizona State University|page=3}}
• April 27 – Herbert Spencer, English philosopher (d. 1903){{cite book|author=Daniel Greenleaf Thompson|title=Herbert Spencer: His Life, Writings, and Philosophy|url=https://books.google.com/books?id=hEMvdumLD3EC&pg=PA4|year=1889|publisher=G.H. Ellis|pages=4}}
• April 26 – Alice Cary, American poet, sister to Phoebe Cary (1824-1871) (d. 1871){{cite book|author=Edwin Francis Hatfield|title=The Poets of the Church: A Series of Biographical Sketches of Hymn-writers with Notes on Their Hymns|url=https://books.google.com/books?id=1X9Na4_B8TsC&pg=PA133|year=1884|publisher=A. D. F. Randolph|pages=133}}
• May 5 – Elkanah Billings, Canadian paleontologist (d. 1876)
• May 12 – Florence Nightingale, English nurse (d. 1910){{cite ODNB |title=Nightingale, Florence (1820–1910), reformer of Army Medical Services and of nursing organization|url=http://www.oxforddnb.com/view/10.1093/ref:odnb/9780198614128.001.0001/odnb-9780198614128-e-35241 |year=2004 |access-date=April 17, 2019 |language=en |doi=10.1093/ref:odnb/35241|last1=Baly |first1=Monica E. |last2=Matthew |first2=H. C. G. |isbn=9780198614128 }}
• May 23 – Lorenzo Sawyer, 9th Chief Justice of the Supreme Court of California (d. 1891)
• May 25 – François Claude du Barail, French general and Minister of War (d. 1902)
• May 27 – Mathilde Bonaparte, Italian princess (d. 1904){{cite book|author=Victor Plarr|title=Men and Women of the Time: A Dictionary of Contemporaries|url=https://books.google.com/books?id=_GwLAQAAIAAJ&pg=PA576|year=1895|publisher=G. Routledge and Sons, limited|pages=576}}

File:Engels.jpg]]

• July 5 – William John Macquorn Rankine, Scottish physicist, engineer (d. 1872)
• July 22 – Oliver Mowat, Canadian lawyer, politician (d. 1903)
• July 23 – Julia Gardiner Tyler, First Lady of the United States (d. 1889)
• July 25 – Henry Doulton, English potter (d. 1897){{cite ODNB|first = Alexander James|last = Clement|title = Doulton, Sir Henry (1820–1897)|id= 7944}}
• September 17
• Émile Augier, French dramatist (d. 1889){{cite book|author=Charles Dudley Warner|title=A Library of the World's Best Literature - Ancient and Modern - Vol.XLII (Forty-Five Volumes); Dictionary of Authors (A-J)|url=https://books.google.com/books?id=0g7UAtyUJYMC&pg=PA29|date=1 July 2008|publisher=Cosimo, Inc.|isbn=978-1-60520-248-8|pages=29}}
• Earl van Dorn, American Confederate general (d. 1863)
• September 20 – John F. Reynolds, American general (d. 1863)
• September 27 – Wilhelm Siegmund Teuffel, German classical scholar (d. 1878)
• September 29 – Henri, Count of Chambord, claimant to the French throne (d. 1883){{cite book|author=Lucian Edward HENRY|title=Europe in 1882: out of the shadow. The Royal Family of France. Twelve lectures on current French History|url=https://books.google.com/books?id=h0cf5yik6u4C&pg=PA66|year=1862|publisher=G. Bishop|pages=66}}
• October 5 – David Wilber, American politician (d. 1890)
• October 6 – Jenny Lind, Swedish soprano (d. 1887){{cite book|title=The Musicians's Year Book|url=https://books.google.com/books?id=U2ZOAAAAMAAJ&pg=PA145|year=1895|publisher=E.P. Dutton|pages=145}}
• October 16 – Gillis Bildt, 5th Prime Minister of Sweden (d. 1894){{cite book |last=Wieselgren |first=Harald |url=https://runeberg.org/wiesminn/0073.html |title=Bilder och minnen |publisher=Beijer |year=1889 |location=Stockholm |pages=73–78 |language=sv |author-link=Harald Wieselgren |access-date=2007-01-19}}
• October 20 – Benjamin F. Cheatham, American Confederate general (d. 1886)
• November 23
• Isaac Todhunter, English mathematician (d. 1884)
• Ludwig von Hagn, German painter (d. 1898){{cite book|author=Munich. Schackgalerie|title=Schack Gallery in Munich: In the Possession of His Majesty the German Emperor, King of Prussia|url=https://books.google.com/books?id=xCcrAAAAIAAJ|year=1911|publisher=G. Hirth|page=69}}
• November 28 – Friedrich Engels, German social philosopher (d. 1895){{cite book|author=V. Ė Kunina|title=Frederick Engels: His Life and Work : Documents and Photographs|url=https://books.google.com/books?id=GdILAAAAYAAJ|year=1987|publisher=Progress|page=18|isbn=9780714725826}}
• December 21 – William H. Osborn, American railroad executive (d. 1894)

• Song Qing, Chinese general (d. 1902)

File:Allan Ramsay - King George III in coronation robes - Google Art Project.jpg]]

• January 17 – Daniel Albert Wyttenbach, Swiss-born academic (b. 1746)
• January 23 – Prince Edward, Duke of Kent and Strathearn, member of British Royal Family and father of Queen Victoria (b. 1767)
• January 29 – King George III of the United Kingdom (b. 1738)
• February 5 – William Drennan, Irish physician, poet and radical politician (b. 1754)
• February 11 – Karl von Fischer, German architect (b. 1782)
• February 14 – Charles Ferdinand, Duke of Berry, French noble (stabbed) (b. 1778)
• March 11 – Benjamin West, Anglo-American painter of historical scenes (b. 1738){{cite book|author=Charles Edwards Lester|title=The Democratic Age: Statesmanship, Science, Art, Literature, and Progress|url=https://books.google.com/books?id=gXsAAAAAYAAJ&pg=PA204|year=1858|publisher=Hale, Valentine & Company|pages=204}}
• March 22 – Stephen Decatur, American sailor (b. 1779){{cite book|author=United States. Congress|title=Congressional Record: Proceedings and Debates of the ... Congress|url=https://books.google.com/books?id=7zs4AQAAMAAJ&pg=PA3133|year=1939|publisher=U.S. Government Printing Office|pages=3133}}
• April 8 – Thomas Douglas, 5th Earl of Selkirk, Scottish-born philanthropist (b. 1771)
• April 20 – James Morris III, Continental Army officer from Connecticut (b. 1752)
• May 30 – William Bradley, Britain's tallest ever man (b. 1787)
• June 6 – Henry Grattan, Irish politician (b. 1746)
• June 9 – Wilhelmina of Prussia, Princess of Orange (b. 1751)
• June 19 – Sir Joseph Banks, English naturalist and botanist (b. 1743){{cite book|author=Edward Edwards|title=Lives of the Founders of the British Museum (etc.) 1570-1870|url=https://books.google.com/books?id=GWloAAAAcAAJ&pg=PA28|year=1870|publisher=Trübner|pages=28}}
• June 20 – Manuel Belgrano, Argentine politician, general in the Independence War (b. 1770){{cite book|author=United States. Office of Inter-American Affairs|title=Air-Mail Feature and Radio Service|url=https://books.google.com/books?id=trJOmjWmVaYC|year=1945|page=2}}

File:清 佚名 《清仁宗嘉庆皇帝朝服像》.jpg]]

• July 10 – William Wyatt Bibb, first Governor of Alabama (b. 1781)
• August 6 – Antonín Vranický, Bohemian violinist and composer (b. 1761){{cite book|author1=David Mason Greene|author2=Constance Green|title=Greene's Biographical Encyclopedia of Composers|url=https://books.google.com/books?id=m3S7PIxe0mwC&pg=PA427|year=1985|publisher=Reproducing Piano Roll Fnd.|isbn=978-0-385-14278-6|pages=427}}
• August 9 – Anders Sparrman, Swedish naturalist (b. 1748)
• August 12 – Manuel Lisa, Spanish-born American fur trader (b. 1772)
• September 2 – Jiaqing Emperor, Chinese emperor (b. 1760)
• September 3 – Benjamin Latrobe, Anglo-American architect (b. 1764)
• September 4 – Timothy Brown, English banker, merchant and radical (b. 1743/1744)
• September 16 – Nguyễn Du, Vietnamese poet (b. 1766)
• September 18 – Mariana Joaquina Pereira Coutinho, Portuguese courtier, salonnière (b. 1748)
• September 26 – Daniel Boone, American pioneer (b. 1734){{cite book|title=The History of Pike County, Missouri: An Encyclopedia of Useful Information, and a Compendium of Actual Facts|url=https://books.google.com/books?id=b9AXz-ZqGU8C&pg=PA200|year=1883|publisher=Mills & Company|pages=200}}
• September 28 – Pedro Andrés del Alcázar, Spanish and later Chilean Army officer and war hero (b. 1752)
• September 29 – Barthelemy Lafon, Creole architect and smuggler (b. 1769)
• October 8 – Henri Christophe, Haitian revolutionary leader (suicide) (b. 1767)
• October 11 – James Keir, Scottish geologist, chemist and industrialist (b. 1735){{cite journal |last = Timmins|first= Sam |title = James Keir, F.R.S., 1735–1820|journal=Transactions (Birmingham and Warwickshire Archaeological Society)|year=1899|pages=1–4|volume=24|url=https://books.google.com/books?id=HV4JAAAAIAAJ&q=james+keir&pg=RA2-PA1}}
• October 15 – Karl Philipp Fürst zu Schwarzenberg, Austrian field marshal (b. 1771)
• November 1 – Pierre Martin, French admiral (b. 1752)
• November 8 – Lavinia Stoddard, American poet and school founder (b. 1787)
• December 25 – Joseph Fouché, French statesman (b. 1759)
• December 29 – Princess Pauline of Anhalt-Bernburg, German regent and social reformer (b. 1769){{Allgemeine Deutsche Biographie|25|275|277|Pauline|August Falkmann|ADB:Pauline}}

{{Reflist}}

{{DEFAULTSORT:1820}}

Category:Leap years in the Gregorian calendar