1817 1818 1819 - 1820 - 1821 1822 1823
| Decades: |
1790s 1800s 1810s - 1820s - 1830s 1840s 1850s
| Centuries: |
18th century - 19th century - 20th century
- January 1 - Constitutionalist military insurrection at [[C�diz]] leads to summoning of Spanish parliament (March 7) and restoration of 1812 Constitution (March 8) by king Ferdinand VII.
- January 29 - George the Prince Regent becomes king George IV of the United Kingdom, ending the period known as the English Regency.
- January 30 - Edward Bransfield discovers Antarctica.
- February 6 - 86 free African American colonists sail from New_York_City&action=edit&redlink=1" class="new" title="REPLACED TAGS 0000000000New YorkREPLACED TAGS 0000000001 City (page does not exist)">New York City to Freetown, Sierra Leone.
- February 23 - The Cato Street conspiracy is exposed. The principals are executed on May 1
- March 3 & March 6 - The Missouri Compromise becomes law in the United States.
- March 15 - Maine is admitted as the 23rd U.S. state.
- May 1 - Last hanging drawing and quartering in Britain – Cato Street conspirators for treason (only hanged and beheaded)
- Spring - Joseph Smith, Jr. at age 14 claims to be visited in a vision by God and Jesus Christ (Tradition holds that this occurred on April 6)
- July - Constitutionalist revolution in the Kingdom of the Two Sicilies
- August 24 - Constitutionalist insurrection at Oporto, Portugal; revolution in Lisbon, September 15
- October 9 - Guayaquil declare independence from Ecuador.
- October 25-November 20 - Congress of Troppau (Opava) between rulers of Russia, Austria and Prussia
- November - James Monroe is re-elected, virtually unopposed.
- November 17 - Captain Nathaniel Palmer becomes the first American to see Antarctica (the Palmer Peninsula was later named after him).
- 6th Edition of Encyclopaedia Britannica begins appearing.
- Republic of Buenos Aires (Argentina) establishes penal colony in Falkland Islands.
- Venus de Milo found on island of Melos.
- Hans Christian Orsted discovers relationship between electricity and magnetism.
- In Salem, Massachusetts, general Robert Jackson eats a tomato in public to prove it is not poisonous
- January 17 - [[Anne Bront�]], author
- February 8 - William Tecumseh Sherman, soldier (+ 1891)
- February 15 - Susan B. Anthony, US suffragist
- February 28 - John Tenniel, illustrator
- March 14 - Victor Emmanuel II of Italy
- May 12 - Florence Nightingale, nurse (+ 1910)
- May 27 - Mathilde Bonaparte, hostess and socialite
- July 23 - Julia Gardiner Tyler, later First Lady of the United States.
- September 27 - Wilhelm Siegmund Teuffel, classical scholar
- September 29 - Henry, Duke of Bordeaux, posthumous son of the Duke of Berry, future Comte de Chambord and claimant to the French throne
- Harriet Tubman, anti-slavery resistance movement leader
- January 29 - King George III of the United Kingdom
- February 14 - Charles Ferdinand, Duke of Berry, stabbed on February 13
- March 22 - Stephen Decatur, sailor
- June 19 - Sir Joseph Banks, British naturalist and botanist
- September 3 - Benjamin Latrobe, architect
- November 23 - Isaac Todhunter, Engrish mathematician (d. 1884)af:1820
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