Events of 1843

January–March

• February 6 – The Virginia Minstrels perform the first minstrel show (Bowery Amphitheatre, New York City).
• February 11 – Giuseppe Verdi's opera I Lombardi premieres in Milan.
• February 14 – The event that inspired the Beatles song Being for the Benefit of Mr. Kite! is held in England.
• March 15 – Victoria, British Columbia, is founded by the Hudson's Bay Company as a trading post and fort.
• March 21 – The world does not end, contrary to the first prediction by American preacher William Miller.

April–June

• May 4 – Natal is proclaimed a British colony.
• May 18 – The Disruption in Edinburgh of the Free Church of Scotland from the Church of Scotland.
• May 22 – The first major wagon train headed for the American Northwest sets out with one thousand pioneers from Elm Grove, Missouri on the Oregon Trail.
• May 23 – Chile takes possession of the Strait of Magellan.
• June 6 – In Barbados, Samuel Jackman Prescod is the first non-white person elected to the House of Assembly.

July–September

• July 1
  • Ulysses S. Grant graduates from West Point 21st from a class of 39.
  • John J. Peck graduates from West Point 8th from a class of 39.
• July 19 – The SS Great Britain is launched from Bristol.
• August 15 – Tivoli Gardens, one of the oldest still intact amusement parks in the world, opens in Copenhagen, Denmark.

• September 3, Popular uprising in Athens, Greece, including citizens and military captains, to require from King Otto to issue a liberal Constitution to the state, which was governed since independence (1830) by various domestic and foreign centres of profits.

October–December

• October 13 – In New York City, Henry Jones and 11 others found B'nai B'rith (the oldest Jewish service organization in the world).
• November 11 – Hans Christian Andersen's The Ugly Duckling is first published.
• November 28 – Ka La Ku'oko'a (Hawaiian Independence Day): The Kingdom of Hawai`i is officially recognized by the United Kingdom of Great Britain and Ireland and July Monarchy France as an independent nation.
• December 19 – Charles Dickens' A Christmas Carol is first published.

Undated

• Saint Louis University School of Law becomes the first law school west of the Mississippi River
• The world's first commercial Christmas cards are printed by Sir Henry Cole in London.
• James Joule quantifies the conversion of work into heat.
• The Danish government re-establishes the Althing in Iceland as an advisory body.
• The first tunnel under the Thames River is finished.
• Argentina supports Rosas of Uruguay and begins a siege of Montevideo.
• Quaternions are discovered by William Rowan Hamilton.
• The Economist is first published.
• Bishop's University is founded.
• Abbeville, Louisiana is founded by descendants of Acadians from Nova Scotia.
• Edgar Allan Poe's short story The Tell-Tale Heart is first published.
• Germans from the Black Forest region of Southern Baden migrate to Venezuela.
• The export of British textile machinery and other equipment is allowed.

Births

January–June

• January 8 – John H. Moffitt, American politician (d. 1926)
• January 10 – Frank James, American outlaw (d. 1915)
• January 29 – William McKinley, 25th President of the United States (d. 1901)
• April 4 – William Jackson, photographer (d. 1942)
• April 15 – Henry James, American writer (d. 1916)
• April 25 – Princess Alice of the United Kingdom, third child of Queen Victoria (d. 1878)
• May 21 – Charles Albert Gobat, Swiss politician, recipient of the Nobel Peace Prize (d. 1914)
• June 3 – King Frederick VIII of Denmark (d. 1912)
• June 9 – Bertha von Suttner, Austrian writer and pacifist, recipient of the Nobel Peace Prize (d. 1914)
• June 15 – Edvard Grieg, Norwegian composer (d. 1907)
• June 30 – Sir Ernest Satow, British diplomat and scholar (d. 1928)

July–December

• July 7 – Camillo Golgi, Italian physician, recipient of the Nobel Prize in Physiology or Medicine (d. 1926)
• July 29 – Johannes Schmidt, German linguist (d. 1901)
• August 1 – Robert Todd Lincoln, American statesman and businessman (d. 1926)
• August 20 – Christina Nilsson, Swedish operatic soprano (d. 1921)
• August 31 – Georg von Hertling, Chancellor of Germany (d. 1919)
• September 4 – Ján Levoslav Bella, Slovak composer (d. 1936)
• November 25 – Henry Ware Eliot, American industrialist, philanthropist and the father of T. S. Eliot (d. 1919)
• November 27 – Cornelius Vanderbilt II, American railway magnate (d. 1899)
• December 11 – Heinrich Hermann Robert Koch, German physician, recipient of the Nobel Prize in Physiology or Medicine (d. 1910)
• December 28 – Colonel Prentiss Ingraham, American author of dime fiction (d. 1904)
• date unknown – Owon, Korean painter (d. 1897)
• probable – Pierre Lallement, French inventor of the bicycle (d. 1891)

Deaths

January–June

• January 11 – Antoine Bournonville, French ballet dancer and choreographer (b. 1760)
• March 21
  • Robert Southey, English poet (b. 1774)
  • Guadalupe Victoria, Mexican revolutionary (b. 1786)
• March 25 – Robert Murray M'Cheyne, Scottish clergyman (b. 1813)
• March 27 – Karl Salomo Zachariae Von Lingenthal, German jurist (b. 1769)
• April 15 – Noah Webster, American lexicographer (b. 1758)
• April 17 – Samuel Morey, American inventor (b. 1762)
• May 28 – Noah Webster, lexicographer (b. 1758)
• June 1 – William Abbot, English actor (b. 1798)
• June 6 – Friedrich Hölderlin, German writer (b. 1770)

July–December

• July or August – Sequoyah, creator of the Cherokee syllabary (b. c. 1767)
• July 7 – John Holmes, American politician (b. 1773)
• July 14 – Miguel de Álava, Spanish soldier and statesman (b. 1770)
• September 11 – Joseph Nicollet, geographer (b. 1786)
• September 16 – Ezekiel Hart, Canadian entrepreneur & politician (b. 1770 or 1767)
• December 12 – King William I of the Netherlands (b. 1772)
• December 18 – Thomas Graham, Lord Lynedoch, British Governor-General of India (b. 1748)