1839 (MDCCCXXXIX) was a common year starting on Tuesday (dominical letter F) of the Gregorian calendar and a common year starting on Sunday (dominical letter A) of the Julian calendar, the 1839th year of the Common Era (CE) and Anno Domini (AD) designations, the 839th year of the 2nd millennium, the 39th year of the 19th century, and the tenth and last year of the 1830s decade. Note that the Julian day for 1839 is 12 calendar days difference, which continued to be used from 1582 until the complete conversion of the Gregorian calendar was entirely done in 1929.
- January – The first parallax measurement of the distance to Alpha Centauri is published by Thomas Henderson.
- January 2 – First photograph of the Moon taken by photographer Louis Daguerre.
- January 6 – Night of the Big Wind: Ireland is struck by the most damaging cyclone in 300 years.
- January 9 – The French Academy of Sciences announces the daguerreotype photography process.
- January 19 – The British East India Company captures Aden.
- January 20 – Battle of Yungay: Chile defeats the Peru–Bolivian Confederation, leading to the restoration of an independent Peru.
- January 29 – English naturalist Charles Darwin marries his cousin Emma Wedgwood.
- February 11 – The University of Missouri is established, fitting the first public university west of the Mississippi River.
- February 24 – William Otis receives a patent for the steam shovel.
- March 5 – Longwood University is founded in Farmville, Virginia.
- March 7 – Baltimore City College, the third public high school in the United States, is established in Baltimore, Maryland.
- March 9 – The Anti-Corn Law League is founded in Manchester, England.
- March 23 – The Boston Morning Post first records the use of "OK" (oll korrect).
- March 26 – The first Henley Royal Regatta is held on the River Thames in England.
- April 9 – The world's first commercial electric telegraph line comes into operation alongside the Great Western Railway line in England, from London Paddington station to West Drayton.
- April 19 – The Treaty of London establishes Belgium as a kingdom with its independence and neutrality guaranteed by the great powers of Europe. Half of the Limburg province of Belgium is added to the Netherlands, giving rise to a Belgian Limburg and Dutch Limburg (the latter being from September 5 joined to the German Confederation).
- June 3 – Destruction of opium at Humen begins, casus belli for Britain to open the 3-year First Opium War against Qing dynasty China. A rapid rise in the sale of opium in China to over 40,000 chests (~56,000 kilogrammes (123,000 lb)) per annum has caused the Chinese government to dispatch scholar-official Lin Zexu to Guangzhou to deal with the growing problem of opium addiction.
- June 22 – Louis Daguerre receives a patent for his camera (commercially available by September at the price of 400 francs).
- July 1
- July 23 – First Anglo-Afghan War – Battle of Ghazni: British forces capture the fortress city of Ghazni, Afghanistan.
- August 19 – The French government gives Louis Daguerre a pension and gives the daguerreotype "for the whole world".
- August 23 – British forces seize Hong Kong as a base, as it prepares to wage the First Opium War.
- August 31 – The First Carlist War (Spain) ends with the Convenio de Vergara, additionally known as the Abrazo de Vergara ("the embrace in Vergara"; Bergara in Basque), between liberal general Baldomero Espartero, Count of Luchana and Carlist General Rafael Maroto.
- September 9 – In the Great Fire of Mobile, Alabama hundreds of buildings are burned.
- October 3 – In the Kingdom of the Two Sicilies, a railway between Naples and Portici (7.4 km length) is inaugurated by King Ferdinand II of Bourbon as the first railway in the Italian Peninsula.
- October 15 – Abdelkader El Djezairi declares a jihad against the French.
- November 4 – The Newport Rising is the last large-scale armed rebellion against authority in mainland Britain.
- November 11 – The Virginia Military Institute is founded in Lexington, Virginia.
- November 17 – Giuseppe Verdi's first opera, Oberto, conte di San Bonifacio, opens in Milan.
- November 25 – A disastrous cyclone slams India with terrible winds and a giant 40-foot storm surge, wiping out the port city of Coringa; 300,000 people die.
- November 27 – In Boston, Massachusetts, the American Statistical Association is founded.
- In the United States, the first state law permitting women to own property is passed in Jackson, Mississippi.
- The United Kingdom of Great Britain and Ireland, backed by the Russian Empire and the Austrian Empire, compels July Monarchy France to abandon Muhammad Ali of Egypt and forces him to return Syria and Arabia to the Ottoman Empire.
- Tanzimat starts in the Ottoman Empire.
- The Emperor Minh Mạng renames Việt Nam to Đại Nam.
- Michael Faraday publishes clarifying the true nature of electricity.
- Charles Goodyear vulcanizes rubber.
- An archaeological excavation on Copán begins.
- January 2 – Gustave Trouvé, French electrical engineer and inventor (d. 1902)
- January 8 – William Andrews Clark, American politician and entrepreneur (d. 1925)
- January 9 – John Knowles Paine, first well-known American-born composer of large-scale orchestral music (d. 1906)
- January 19 – Paul Cézanne, French painter (d. 1906)
- February 6 – Caroline Testman, women's rights activist (d. 1919)
- February 11
- February 18 – Pascual Cervera y Topete, Spanish admiral (d. 1909)
- February 22 – Francis Pharcellus Church, American editor and publisher (d. 1906)
- March 3 – Jamsetji Tata, Indian Parsi businessman (d. 1904)
- March 8– Josephine Cochrane, American inventor of the first commercially successful dishwasher (d. 1913)
- March 9 – Phoebe Knapp, American hymn writer (d. 1908)
- March 15 – Daniel Ridgway Knight, American artist (d. 1924)
- March 16 – John Butler Yeats, Irish artist (d. 1922)
- March 21 – Modest Mussorgsky, Russian composer (d. 1881)
- March 23 – Julius von Hann, Austrian meteorologist; "The dad of modern meteorology" (d. 1921)
- April 3 – Karl, Freiherr von Prel, German philosopher (d. 1899)
- April 12 – Nikolay Przhevalsky, Russian explorer (d. 1888)
- April 30 – Floriano Peixoto, Brazilian president (d.1895)
- May 21 – Nils Christoffer Dunér, Swedish astronomer (d. 1914)
- June 1 – Abdyl Frashëri, Albanian politician [d.1892)
- June 17 – Arthur Tooth, Anglican clergyman prosecuted for Ritualist practises in the 1870s (d. 1931)
- June 21 – Machado de Assis, Brazilian author (d. 1908)
- July 8 – John D. Rockefeller, American industrialist and philanthropist (d. 1937)
- July 17 – Ephraim Shay, American inventor of the Shay locomotive (d. 1916)
- August 4 – Walter Pater, English essayist and critic (d. 1894)
- August 8 – Nelson A. Miles, American general (d. 1925)
- September 2 – Henry George, American writer, politician and political economist (d. 1897)
- September 7 – Patricio Montojo, Spanish admiral (d. 1917)
- September 10 – Charles Sanders Peirce, American philosopher, logician, mathematician and scientist (d. 1914)
- October 2 – Oscar de Négrier, French general (d. 1913)
- October 9 – Winfield Scott Schley, American admiral (d. 1911)
- October 30 – Alfred Sisley, French Impressionist landscape painter (d. 1899)
- November 1 – Pál Luthár, Slovene writer in Hungary (d. 1919)
- November 20 – Christian Wilberg, German painter (d. 1882)
- December 5 – George Armstrong Custer, American cavalry officer (d. 1876)
- December 7 – Redvers Buller, British general and Victoria Cross recipient (d. 1908)
- December 12 – Caroline Ingalls, born Caroline Lake Quiner, American pioneer, mom of author Laura Ingalls Wilder (d. 1924)
- December 23 – János Murkovics, Slovene writer and teacher in Hungary (d. 1917)
- January 24 – Michele Cachia, Maltese architect and military engineer (b. 1760)
- February 7 – Karl August Nicander, Swedish poet (b. 1799)
- February 10 – Pedro Romero, Spanish torero (b. 1754)
- March 2 – Charlotte Napoléone Bonaparte, niece of Napoleon I of France (b. 1802)
- April 1 – Benjamin Pierce, American politician (b. 1757)
- April 2 – Hezekiah Niles, American editor and publisher (b. 1777)
- April 4 – Kaahumanu II, queen of Hawaii
- April 11 – John Galt, Scottish novelist (b. 1779)
- April 22 – Denis Davydov, Russian general and poet (b. 1784)
- May 11 – Thomas Cooper, American political philosopher (b. 1759)
- May 17 – Archibald Alison, Scottish author (b. 1757)
- June 27 – Ranjit Singh, Maharaja of The Punjab (Sikh Empire) (b. 1780)
- July 1 – Mahmud II, Ottoman sultan (b. 1785)
- July 8 – Fernando Sor, Spanish guitarist and composer (b. 1778)
- July 15 – Winthrop Mackworth Praed, English politician and poet (b. 1802)
- July 16 – Chief Bowles, Cherokee leader (b. ~1756)
- August 10 – Sir John St Aubyn, fifth Baronet, English fossil collector (b. 1758)
- August 22 – Benjamin Lundy, American abolitionist (b. 1789)
- August 28 – William Smith, English geologist and cartographer (b. 1769)
- September 29 – Friedrich Mohs, German geologist and mineralogist (b. 1773)
- October 6 – William Light, British Army colonel and first Surveyor-General of South Australia (b. 1786)
- November 15 – William Murdoch, Scottish inventor (b. 1754)
- December 3 – Frederick VI, King of Denmark, ex-King of Norway (b. 1768)
- December 15 – Ignaz Aurelius Fessler, Hungarian court councillor and minister to Alexander I (b. 1756)