1834

January–March

• January 1 – Zollverein (Germany): Customs charges are abolished at borders within its member states.
• January 3 – The government of Mexico imprisons Stephen F. Austin in Mexico City.
• February 13 – Robert Owen organizes the Grand National Consolidated Trades Union in the United Kingdom.^[1]
• March 6 – York, Upper Canada, is incorporated as Toronto.
• March 11 – The United States Survey of the Coast is transferred to the Department of the Navy.
• March 14 – John Herschel discovers the open cluster of stars now known as NGC 3603, observing from the Cape of Good Hope.^[2]
• March 28 – Andrew Jackson is censured by the United States Congress (expunged in 1837).

April–June

• April 10 – The LaLaurie mansion in New Orleans burns, and Madame Marie Delphine LaLaurie flees to France.
• April 14 – The Whig Party is officially named, by United States Senator Henry Clay.
• May 19 – The Syrian Peasant Revolt (1834–35) erupts in Egyptian-ruled Ottoman Syria, encompassing peasant uprisings in Palestine and Transjordan, Galilee and Hauran and the Syrian coast; the rebellions are suppressed with harsh military response leading to thousands of deaths and mostly subdued by August, though Syrian coast uprising lasts by early 1835.
• June 7 – Greek independence: General Theodoros Kolokotronis is sentenced to death for treason, for resisting the rule of Otto of Greece (he is released the following year).
• June 10 – British philosopher Thomas Carlyle moves to Cheyne Row (Carlyle's House) in London.
• June 21 – American inventor and businessman Cyrus McCormick is granted a patent, for his mechanical reaper.

July–September

• July 7 – 10 – Anti-abolitionist riots break out in New York City.
• July 15 – The Spanish Inquisition, which began in the 15th century, is suppressed by royal decree.
• July 16 – William Lamb, 2nd Viscount Melbourne succeeds Earl Grey as Prime Minister of the United Kingdom.
• July 24 – The Liberal Wars end in Portugal.
• July 29 – The Office of Indian Affairs is organized in the United States.
• August 1 – Slavery is abolished in the British Empire, by the Slavery Abolition Act 1833.
• August 11–12 – Ursuline Convent riots: A convent of Ursuline nuns is burned near Boston.
• August 12 – In the Empire of Brazil, the Additional Act provides for establishment of the Provincial Legislative Assembly, extinction of the State Council, replacement of the Regency Trina, and introduction of a direct and secret ballot.
• August 14 – The Poor Law Amendment Act in the United Kingdom states that no able-bodied British man can receive assistance, unless he enters a workhouse (a kind of poorhouse).
• August 15 – The South Australia Act allows for the creation of a colony there.
• September – The Economist newspaper is first published in London.
• September 13 – The Gleaner newspaper is first published in Jamaica.

October–December

• October 16 – The Palace of Westminster is destroyed by fire.
• November 14 – William Lamb, 2nd Viscount Melbourne becomes the last Prime Minister of the United Kingdom to be dismissed by the British monarch. King William IV temporarily appoints Arthur Wellesley, 1st Duke of Wellington, to form a caretaker government.^[3][4]
• December 3 – The Zollverein institutes the first regular census in Germany. The population is 23,478,120.
• December 10 – Sir Robert Peel succeeds Lord Melbourne, as Prime Minister of the United Kingdom.
• December 11 – The Sixth Xhosa War is characterized by severe clashes between white settlers and Bantu peoples in Cape Colony; Dutch-speaking settlers colonize the area north of Orange River.

Date unknown

• A pro-republic uprising fails in Piedmont; one of the activists is Giuseppe Garibaldi.
• The British East India Company monopoly on China trade ends.
• Athens becomes Greece's capital city.
• The Medical School of Louisiana (later Tulane University) is founded in New Orleans.
• Charles Babbage begins the conceptual design of the Analytical Engine, a mechanical forerunner of the modern computer. It will not be built in his lifetime.^[5][6]
• Thomas Davenport, inventor of the first American DC electrical motor, installs his motor in a small model car, creating one of the first electric cars.
• The Wilmington and Raleigh Railroad is chartered in Wilmington, North Carolina.^[7]
• The Romanian language is banned in schools and government facilities, in Bessarabia.^[8]

January–June

• January 7 – Johann Philipp Reis, German physicist, inventor (d. 1874)
• January 15 – Samuel Arza Davenport, American politician (d. 1911)
• January 17 – August Weismann, German evolutionary biologist (d. 1914)
• January 20 – Piet Joubert, Boer politician, military commander (d. 1900)
• January 25 – Alina Frasa, Finnish ballerina (d. 1899)
• February 6 – Edwin Klebs, German-Swiss pathologist who discovered Diphtheria (d. 1913)
• February 8 – Dmitri Mendeleev, Russian chemist (d. 1907)
• February 9 – Felix Dahn, German author (d. 1912)
• February 16 – Ernst Haeckel, German zoologist, philosopher (d. 1919)
• February 19 – Charles Davis Lucas, British Victoria Cross recipient (d. 1914)
• February 27 – Charles C. Carpenter, American admiral (d. 1899)
• March 5 – Félix de Blochausen, 6th Prime Minister of Luxembourg (d. 1915)
• March 16 – James Hector, Scottish geologist (d. 1907)

Gottlieb Daimler.

• March 17 – Gottlieb Daimler, German engineer, inventor (d. 1900)
• March 20 – Charles W. Eliot, American President of Harvard University (d. 1926)
• March 23 – Julius Reubke, German composer (d. 1858)
• March 24
  • John Wesley Powell, American explorer (d. 1902)
  • William Morris, English poet, artist (d. 1896)
• April 1 – Big Jim Fisk, American entrepreneur (d. 1872)
• April 26 – Artemus Ward, American humorist (d. 1867)
• May 20 – Albert Niemann, German chemist (d. 1861)
• May 23 – Carl Heinrich Bloch, Danish sculptor (d. 1890)
• June 19 – Charles Spurgeon, English Baptist preacher (d. 1892)

July–December

• July 2 – Hendrick Peter Godfried Quack, Dutch economist, historian (d. 1917)
• July 10 – James McNeill Whistler, American painter, etcher (d. 1903)
• July 12 – Elisabeth Howen, Estonian reform educator (d. 1923)
• July 19 – Edgar Degas, French painter (d. 1917)
• July 2 – Frédéric Auguste Bartholdi, French sculptor (d. 1904)
• August 4 – John Venn, British mathematician (d. 1923)
• August 22 – Samuel Pierpont Langley, American astronomer, physicist, and aeronautics pioneer (d. 1906)
• August 31 – Amilcare Ponchielli, Italian composer (d. 1886)
• September 9 – Joseph Henry Shorthouse, English novelist (d. 1903)
• September 17 – Robert Simpson (merchant), Scottish-Canadian businessman (d. 1897)
• September 30 – Louis P. Mouillard, French artist, aviation pioneer (d. 1897)
• October 6 – Walter Kittredge, American composer (d. 1905)
• November 8 – Johann Karl Friedrich Zöllner, German astrophysicist (d. 1882)
• November 19 – Georg Hermann Quincke, German physicist (d. 1924)
• November 21 – Hetty Green, American businesswoman (d. 1916)
• December 16 – Léon Walras, French economist (d. 1910)
• December 24 – Augustus George Vernon Harcourt, English chemist (d. 1919)

Date unknown

• Giorgio Costantino Schinas, Maltese architect and civil engineer (d. 1894)

January–June

• January 12 – William Grenville, 1st Baron Grenville, Prime Minister of the United Kingdom (b. 1759)
• January 17 – Giovanni Aldini, Italian physicist (b. 1762)
• February 2 – Lorenzo Dow, American minister (b. 1777)
• February 4 – Amélie-Julie Candeille, French composer, librettist, writer, singer, actress, comedian, and instrumentalist (b. 1767)
• February 12 – Friedrich Schleiermacher, German theologian (b. 1768)
• February 18 – William Wirt, 9th United States Attorney General (b. 1772)
• February 23 – Karl Ludwig von Knebel, German poet (b. 1744)
• March 2 – José Cecilio del Valle, first President of Central America (b. 1780)
• March 30 – Rudolph Ackermann, Anglo-German entrepreneur (b. 1764)
• April 5 – Vice-Admiral Sir Richard Goodwin Keats, Governor of Newfoundland (b. 1757)
• April 10 – John 'Merino' MacArthur, Australian farmer (b. 1767)
• April 11 – John 'Mad Jack' Fuller, English philanthropist, patron of the arts and sciences (b. 1757)
• April 29 – Grigore IV Ghica, prince of Wallachia (b. 1755)
• May 20 – Gilbert du Motier, Marquis de Lafayette, French nobleman, soldier (b. 1757)

July–December

• July 12 – David Douglas, Scottish botanist (b. 1799)
• July 14 – Edmond-Charles Genêt, French ambassador to the United States during the French Revolution (b. 1763)
• July 19 – Károly Hadaly, Hungarian mathematician (b. 1743)
• July 25 – Samuel Taylor Coleridge, English writer (b. 1772)
• August 1 – Robert Morrison, British Protestant missionary to China (b. 1782)
• August 7 – Joseph Marie Jacquard, French inventor (b. 1752)
• August 17 – Husein Gradaščević, Bosnian rebel leader (b. 1802)
• September 2 – Thomas Telford, Scottish engineer (b. 1757)
• September 5 – Thomas Lee, English architect (b. 1794)
• September 9 – James Weddell, Antarctic explorer (b. 1787)
• September 15 – William H. Crawford, American politician, judge (b. 1772)
• September 16 – William Blackwood, Scottish writer (b. 1776)
• September 24 – Emperor Pedro I of Brazil (b. 1798)
• October 8 – François-Adrien Boieldieu, French composer (b. 1775)
• October 11 – William Napier, 9th Lord Napier, British Navy officer, politician and diplomat (b. 1786)
• October 23 – Fath Ali Shah Qajar, King of Iran (b. 1772)
• November 2 – Maria Teresa Poniatowska, Polish aristocrat (b. 1760)
• November 27 – Rosalie de Constant, Swiss naturalist (b. 1758)
• December 23 – Thomas Malthus, English economist, political philosopher (b. 1766)
• December 27 – Charles Lamb, English essayist (b. 1775)
• December 31 – João Batista Gonçalves Campos, intellectual leader of the Cabanagem social revolt, in the vice-Kingdom of Grão-Pará, Brazil (b. 1782)