* January – The first parallax measurement of the distance to Alpha Centauri is published by Thomas Henderson. * January 2 – The first photograph of the Moon is taken, by French photographer Louis Daguerre. * January 6Night 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 – British forces capture Aden. * January 20Battle of Yungay: Chile defeats the Peru–Bolivian Confederation, leading to the restoration of an independent Peru. * February 11 – The University of Missouri is established, becoming the first public university west of the Mississippi River. * February 24William Otis receives a patent for the steam shovel. * March 5Longwood University is founded in Farmville, Virginia. * March 7Baltimore 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 "O.K." (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 joined (from September 5) to the German Confederation). * April 24Boston University is established as the Newbury Biblical Institute in Vermont. * May 7 – The Bedchamber Crisis begins in the United Kingdom, after Prime Minister Lord Melbourne announces his resignation. Queen Victoria asks several MPs to form a new government, and they insist on the condition that the Queen dismiss several of her personal attendants, the ladies of the bedchamber, for political reasons. * May 12 – Socialist activist Louis Auguste Blanqui and the ''Société des Saisons'' begin an uprising against the government of France. The insurrection is suppressed, but not before 50 people are killed and 190 wounded. Blanqui is imprisoned until 1848. * May 22 – Former British statesman Lord Durham, as President of the New Zealand Company, formally asks the British government for permission to colonize New Zealand, and to establish a colonial government under the sovereignty of the United Kingdom. * May 23 – Turkish troops cross the Euphrates River and invade Syria, but are defeated in battle in June. * June 3Destruction 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 (~) per annum results. has caused the Chinese government to dispatch scholar-official Lin Zexu to Guangzhou to deal with the growing problem of opium addiction. * June 22Louis Daguerre receives a patent for his camera (commercially available by September at the price of 400 francs).


* July 1 ** Slaves aboard the ''Amistad'' rebel, and capture the ship. ** Abdülmecid I (1839–1861) succeeds Mahmud II (1808–1839) as Ottoman Emperor. * July 23First Anglo-Afghan WarBattle of Ghazni: British forces capture the fortress city of Ghazni, Afghanistan. * August 8 – The Fraternity of Beta Theta Pi is founded by John Reily Knox at Miami University. * August 19 – The French government gives the daguerreotype "for the whole world". * August 31 – The First Carlist War (Spain) ends with the Convenio de Vergara, also 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 4Battle of Kowloon: British vessels open fire on Chinese war junks enforcing a food sales embargo on the British community in China in the first armed conflict of the First Opium War.


* October 3 – A railway between Naples and Portici () in the Kingdom of the Two Sicilies is inaugurated by King Ferdinand II of Bourbon as the first line in the Italian Peninsula. * October 15Emir Abdelkader declares a jihad against the French. * November 4Newport Rising: Between 5,000 and 10,000 Chartist sympathisers march on Newport, Monmouthshire, to liberate Chartist prisoners; around 22 are killed when troops fire on the crowd. This is the last large-scale armed civil rebellion against authority in mainland Britain and sees the most deaths. * November 11 – The Virginia Military Institute is founded in Lexington, Virginia. * November 17Giuseppe Verdi's first opera, ''Oberto, conte di San Bonifacio'', opens in Milan. * November 25 – A disastrous cyclone hits India with terrible winds and a giant 40-foot storm surge, wiping out the port city of Coringa; 300,000 people die. * November 27 – The American Statistical Association is founded in Boston, Massachusetts. * December 6 – The Whig Party (United States), at its first ever national convention, in Harrisburg, Pennsylvania, nominates former U.S. Army General William Henry Harrison to be its candidate for President of the United States in the 1840 election. Although Senator Henry Clay of Kentucky has received 103 of the 128 necessary votes on the first ballot, he obtains only 90 on the final vote, while Harrison gets 148. Former U.S. Senator John Tyler is unanimously nominated for vice president.

Date unknown

* 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. * Emperor Minh Mạng renames Việt Nam to Đại Nam. * Michael Faraday publishe
"Experimental Researches in Electricity"
clarifying the true nature of electricity. * Charles Goodyear vulcanizes rubber. * An archaeological excavation on Copán begins. * Khalid bin Saud Al Suad usurps the throne from Faisal bin Turki bin Abdullah Al Saud, who assumed power of Nejd in 1834, and is sent to Cairo as prisoner. Omar bin Ofaysan, the Amir Faisal's governor in the Eastern Province seeks asylum in Bahrain, but Khalid the pretender demands his surrender and the surrender of the fort at Dammam; then under the control of the Al Khalifa of Bahrain. * Khorshid Pasha vows to attack Bahrain to exert Egyptian rule over Bahrain, but his attack is prevented after Shaikh Abdulla bin Ahmed of Bahrain pays tribute. * A quarrel broke out between the Chief of Abu Dhabi of the Beniyas tribe, Shaikh Khalifa bin Shakboot, and the fugitives who settled there after their departure from Bahrain, the Al Binali tribe. Under the command of their leader, Isa bin Tureef Al Binali, they relocate to Kenn Island where they exercise depredations over the Bahrain and other Gulf vessels. Their motive, to restore their belongings which they abandoned upon leaving Bahrain. * Valley Falls Company, as predecessor of Berkshire Hathaway, a conglomerate and holdings business in United States, was founded in Rhode Island. * Chattanooga, Tennessee is incorporated as a town



* January 2Gustave Trouvé, French electrical engineer, inventor (d. 1902) * January 8William A. Clark, American politician, entrepreneur (d. 1925) * January 9John Knowles Paine, American composer (d. 1906) * January 19Paul Cézanne, French painter (d. 1906) * January 26Rachel Lloyd, American chemist (d. 1900) * February 6Caroline Testman, Danish women's rights activist (d. 1919) * February 11 ** Josiah Willard Gibbs, American physicist, chemist (d. 1903) ** Almon Brown Strowger, American telecommunications engineer (d. 1902) * February 18Pascual Cervera y Topete, Spanish admiral (d. 1909) * February 22Francis Pharcellus Church, American editor, publisher (d. 1906) * March 3Jamsetji Tata, Indian Parsi businessman (d. 1904) * March 8Josephine Cochrane, American inventor of the first commercially successful dishwasher (d. 1913) * March 15Daniel Ridgway Knight, American artist (d. 1924) * March 16 ** Sully Prudhomme, French poet, critic, Nobel Prize laureate (d. 1907) ** John Butler Yeats, Irish artist (d. 1922) * March 21Modest Mussorgsky, Russian composer (d. 1881) * March 23Julius von Hann, Austrian meteorologist (''The father of modern meteorology'') (d. 1921) * March 25 ** Carlo Pellegrini, Italian caricaturist (d. 1889) ** Marianne Hainisch, founder, leader of the Austrian women's movement (d. 1936) * March 27John Ballance, 14th Premier of New Zealand (d. 1893) * April 3Karl, Freiherr von Prel, German philosopher (d. 1899) * April 8Belle L. Pettigrew, American teacher, missionary (d. 1912) * April 12Nikolay Przhevalsky, Russian explorer (d. 1888) * April 16Antonio Starabba, Marchese di Rudinì, 12th Prime Minister of Italy (d. 1908) * April 30 ** Floriano Peixoto, 2nd President of Brazil (d. 1895) ** Yoshitoshi, Japanese artist (d. 1892) * May 14Frederic W. Tilton, American educator and 7th Principal of Phillips Academy in Andover, Massachusetts (d. 1918) * May 21Mary of the Passion, French Roman Catholic religious sister, missionary, and blessed (d. 1904) * June 1Abdyl Frashëri, Albanian politician (d.1892) * June 10Ludvig Holstein-Ledreborg, Prime Minister of Denmark (d. 1912) * June 17Arthur Tooth, Anglican clergyman prosecuted for Ritualist practices in the 1870s (d. 1931) * June 21Machado de Assis, Brazilian author (d. 1908)


* July 6Édouard Pottier, French admiral (d. 1903) * July 8John D. Rockefeller, American industrialist, philanthropist (d. 1937) * July 17Ephraim Shay, American inventor of the Shay locomotive (d. 1916) * July 18James Surtees Phillpotts, English author (d. 1930) * July 28Isabelle Gatti de Gamond, Italo-Belgian educationalist, feminist, and politician (d. 1905) * July 31Ignacio Andrade, 37th President of Venezuela (d. 1925) * August 4Walter Pater, English essayist, critic (d. 1894) * August 8Nelson A. Miles, American general (d. 1925) * August 15Antonín Petrof, Czech piano maker (d. 1915) * September 2Henry George, American writer, politician, and political economist (d. 1897) * September 7Patricio Montojo y Pasarón, Spanish admiral (d. 1917) * September 10Charles Sanders Peirce, American philosopher, logician, mathematician, and scientist (d. 1914) * September 12Mary H. Graves, American minister, literary editor, writer (d. 1908) * October 2Oscar de Négrier, French general (d. 1913) * October 9 ** Georges Leclanché, French electrical engineer, inventor (d. 1882) ** Winfield Scott Schley, American admiral (d. 1911) * October 11Jeanne Merkus, Dutch deaconess, guerilla soldier, and political activist (d. 1897) * October 30Alfred Sisley, French Impressionist landscape painter (d. 1899) * November 1Pál Luthár, Slovene writer in Hungary (d. 1919) * November 12Frank Furness, American architect, soldier (d. 1912) * November 18Emil Škoda, Czech engineer, industrialist (d. 1900) * November 20Christian Wilberg, German painter (d. 1882) * November 30Catherine Amanda Coburn, American journalist, newspaper editor (d. 1913) * December 5George Armstrong Custer, American cavalry officer (d. 1876) * December 7Sir Redvers Buller, British general, Victoria Cross recipient (d. 1908)

Date unknown

* Avis Crocombe, English cook at Audley End House



* January 24Michele Cachia, Maltese architect, military engineer (b. 1760) * February 7Karl August Nicander, Swedish poet (b. 1799) * February 10Pedro Romero, Spanish torero (b. 1754) * March 2Charlotte Napoléone Bonaparte, niece of Napoleon I of France (b. 1802) * March 20Caspar Voght, German businessman (b. 1752) * April 1Benjamin Pierce, American politician (b. 1757) * April 2Hezekiah Niles, American editor, publisher (b. 1777) * April 4 – Queen Kaahumanu II of Hawaii * April 11John Galt, Scottish novelist (b. 1779) * April 22 ** Denis Davydov, Russian general, poet (b. 1784) ** Samuel Smith (Maryland politician), American politician (b. 1752) * May 11 ** Thomas Cooper, American political philosopher (b. 1759) ** William Farquhar, First British Resident and Commandant of colonial Singapore (b. 1774) * May 17Archibald Alison, Scottish author (b. 1757) * June 23Lady Hester Stanhope, English archaeologist (b. 1776) * June 27Ranjit Singh, Maharaja of The Punjab (Sikh Empire) (b. 1780)


* July 1Mahmud II, Ottoman sultan (b. 1785) * July 8Fernando Sor, Spanish guitarist, composer (b. 1778) * July 15Winthrop Mackworth Praed, English politician, poet (b. 1802) * July 16Chief Bowles, Cherokee leader (b. ~1756) * July 19Maurice de Guérin, French poet (b. 1810) * August 10Sir John St Aubyn, 5th Baronet, English fossil collector (b. 1758) * August 22Benjamin Lundy, American abolitionist (b. 1789) * August 28William Smith, English geologist, cartographer (b. 1769) * September 10James Maitland, 8th Earl of Lauderdale, Scottish politician (b. 1759) * September 29Friedrich Mohs, German geologist, mineralogist (b. 1773) * October 6William Light, British Army colonel, first Surveyor-General of South Australia (b. 1786) * October 11Leonor de Almeida Portugal, 4th Marquise of Alorna, Portuguese painter, poet (b. 1750) * November 15William Murdoch, Scottish inventor (b. 1754) * December 3Frederick VI, King of Denmark, ex-King of Norway (b. 1768) * December 4John Leamy, Irish–American merchant (b. 1757) * December 15Ignaz Aurelius Fessler, Hungarian court councillor, minister to Alexander I (b. 1756) * December 26Laurent Jean François Truguet, French admiral (b. 1752)