|Covid-19|January 4 – The New York Stock Exchange opens its first permanent headquarters at 10-12 Broad near Wall Street in New York City.
January 13 – American Civil War: The Second Battle of Fort Fisher begins when United States forces launch a major amphibious assault against the last seaport held by the Confederates, Fort Fisher, North Carolina.
January 15 – American Civil War: United States forces capture Fort Fisher.
Thirteenth Amendment to the United States Constitution (conditional prohibition of slavery and involuntary servitude) passes narrowly in the House of Representatives.
American Civil War: Confederate General Robert E. Lee becomes general-in-chief.
February – American Civil War: Columbia, South Carolina burns as Confederate forces flee from advancing Union forces.
February 3 – Leaders from Union and Confederacy discuss peace terms at the Hampton Roads Conference.
February 8 & March 8 – Gregor Mendel reads his paper on Experiments on Plant Hybridization at two meetings of the Natural History Society of Brünn in Moravia, subsequently taken to be the origin of the theory of Mendelian inheritance.
February 21 – John Deere receives a patent for ploughs.
February 22 – Tennessee adopts a new constitution that abolishes slavery.
March 3 – The U.S. Congress authorizes formation of the Bureau of Refugees, Freedmen and Abandoned Lands.
March 4 – Abraham Lincoln is sworn in for a second term as President of the United States.
March 4 – Washington College and Jefferson College are merged to form Washington & Jefferson College.
March 13 – American Civil War: The Confederate States of America agrees to the use of African American troops.
March 18 – American Civil War: The Congress of the Confederate States of America adjourns for the last time.
March 19 – American Civil War: The Battle of Bentonville begins; by the end of the battle on March 21 the Confederate forces retreat from Four Oaks, North Carolina.
The "Claywater Meteorite" explodes just before reaching ground level in Vernon County, Wisconsin; fragments having a combined mass of 1.5 kg are recovered.
American Civil War: In Virginia, Confederate forces capture Fort Stedman from the Union. Lee's army suffers heavy casualties during the battle of Fort Stedman—about 2,900, including 1,000 captured in the Union counterattack. Confederate positions are weakened. After the battle, Lee's defeat is only a matter of time.
April 1 – American Civil War – Battle of Five Forks: In Petersburg, Virginia, Confederate General Robert E. Lee begins his final offensive.
April 2 – American Civil War: Confederate President Jefferson Davis and most of his Cabinet flee the Confederate capital of Richmond, Virginia, which is taken by Union troops the next day.
April 6 – German chemicals producer Badische Anilin- und Sodafabrik (BASF) is founded in Mannheim.
April 9 – American Civil War: Confederate States Army General Robert E. Lee surrenders to Union Army General Ulysses S. Grant at Appomattox Court House, effectively ending the American Civil War.
April 14 (Good Friday)
Assassination of Abraham Lincoln: President of the United States Abraham Lincoln is shot while attending an evening performance of the farce Our American Cousin at Ford's Theatre in Washington, D.C. by actor and Confederate sympathizer John Wilkes Booth. Doctors move the unconscious President to a bed in a house across the street.
United States Secretary of State William H. Seward and his family are attacked in his home by Lewis Powell.
April 15 – President Lincoln dies early this morning from his gunshot wound. Vice President Andrew Johnson becomes President of the United States, upon Lincoln's death. Johnson is sworn in later that morning.
April 18 – Confederate President Jefferson Davis and his entire cabinet arrive in Charlotte, North Carolina with a contingent of 1,000 soldiers.
April 21 – German Chemicals producer BASF moves its headquarters and factories from Mannheim to the Hemshof District of Ludwigshafen.
American Civil War: Confederate States Army General Joseph E. Johnston surrenders to Union Army Major General William Tecumseh Sherman at Durham Station, North Carolina.
Union cavalry corner John Wilkes Booth in a Virginia barn, and cavalryman Boston Corbett shoots the assassin dead.
The steamboat Sultana, carrying 2,300 passengers, explodes and sinks in the Mississippi River, killing 1,800, mostly Union survivors of the Andersonville Prison.
Governor of New York Reuben Fenton signs a bill formally creating Cornell University in the United States.
May 1 – The Triple Alliance of Argentina, Brazil, and Uruguay against Paraguay is formally signed; the Paraguayan War has already begun.
May 4 – American Civil War: Lieutenant General Richard Taylor, commanding all Confederate forces in Alabama, Mississippi, and eastern Louisiana, surrenders his forces to Union General Edward Canby at Citronelle, Alabama, effectively ending all Confederate resistance east of the Mississippi River.
In North Bend, Ohio (a suburb of Cincinnati), the first train robbery in the United States takes place.
Jefferson Davis meets with his Confederate Cabinet (14 officials) for the last time, in Washington, Georgia, and the Confederate Government is officially dissolved.
May 10 – American Civil War: Jefferson Davis is captured by the Union Army near Irwinville, Georgia.
May 12–May 13 – American Civil War – Battle of Palmito Ranch: In far south Texas, more than a month after Confederate General Lee's surrender, the last land battle of the civil war with casualties ends with a Confederate victory.
International Telegraph Union founded.
French missionary Father Armand David first observes Père David's deer in Peking, China.
May 23 – Grand Review of the Armies: Union Army troops parade down Pennsylvania Avenue (Washington, D.C.) to celebrate the end of the American Civil War.
May 25 – Mobile magazine explosion: 300 are killed in Mobile, Alabama when an ordnance depot explodes.
May 29 – American Civil War: President of the United States Andrew Johnson issues a proclamation of general amnesty for most citizens of the former Confederacy.
June–August – English polymath Francis Galton formulates eugenics.
June 2 – American Civil War: Confederate forces west of the Mississippi River under General Edmund Kirby Smith surrender at Galveston, Texas under terms negotiated on May 26, becoming the last to do so.
June 10 – Richard Wagner's opera Tristan und Isolde debuts at the Munich court theatre.
June 11 – Battle of the Riachuelo: The Brazilian Navy squadron defeats the Paraguayan Navy.
June 19 – American Civil War: Union Major General Gordon Granger lands at Galveston, Texas and informs the people of Texas of the Emancipation Proclamation (an event celebrated in modern times each year as Juneteenth).
June 23 – American Civil War: At Fort Towson in Oklahoma Territory, Confederate General Stand Watie, a Cherokee Indian, surrenders the last significant Rebel army.
June 25 – James Hudson Taylor founds the China Inland Mission at Brighton, England.
July – The Christian Mission, later renamed The Salvation Army, is founded in Whitechapel, London by William and Catherine Booth.
July 4 – Lewis Carroll publishes his children's novel Alice's Adventures in Wonderland in England (first trade editions in December).
The U.S. Secret Service is founded.
The first speed limit is introduced in Britain: 2 mph (3.2 km/h) in town and 4 mph (6.4 km/h) in the country.
July 7 – Following Abraham Lincoln's assassination on April 14, the four conspirators condemned to death during the trial are hanged, including David Herold, George Atzerodt, Lewis Payne and Mary Surratt. Her son, John Surratt, escapes execution by fleeing to Canada, and ultimately to Egypt.
July 14 – First ascent of the Matterhorn: The summit of the Matterhorn in the Alps is reached for the first time, by a party of seven led by the Englishman Edward Whymper; four die in a fall during the descent.
July 21 – Wild Bill Hickok – Davis Tutt shootout: In the market square of Springfield, Missouri, Wild Bill Hickok shoots Little Dave Tutt dead over a poker debt in what is regarded as the first true western "fast draw" showdown.
July 27 – Welsh settlers arrive in Argentina at Chubut Valley.
July 30 – The steamer Brother Jonathan sinks off the California coast, killing 225.
July 31 – The first narrow gauge mainline railway in the world opens at Grandchester, Australia.
August 16 – The Dominican Republic regains independence from Spain
August 25 – The Shergotty meteorite Mars meteorite falls in Sherghati, Gaya, Bihar, India.
September 19 – Union Business College (now Peirce College) is founded in Philadelphia.
September 26 – Champ Ferguson becomes the first person (and one of only two) to be convicted of war crimes for actions taken during the American Civil War, found guilty by a U.S. Army tribunal on 23 charges arising from the murder of 53 people. He is hanged on October 20, two days after the conviction of Henry Wirz for war crimes.
October 11 – Paul Bogle leads hundreds of black men and women in a march in Jamaica, starting the Morant Bay rebellion.
October 25 &ndsh; Florida drafts its constitution in Tallahassee.
The Standard Oil Company opens
The paddlewheel steamer SS Republic sinks off the Georgia coast, with a cargo of $400,000 in coins.
November 6 – American Civil War: Surrender to the British at Liverpool of the commerce raider CSS Shenandoah (Captain James Waddell), the last significant organized Confederate unit.
November 10 – Major Henry Wirz, the superintendent of a prison camp in Andersonville, Georgia, is hanged, becoming the first of two American Civil War soldiers to be executed for war crimes.
November 26 – Battle of Papudo: The Spanish ship Covadonga is captured by the Chileans and the Peruvians, north of Valparaíso, Chile.
December 11 – The United States Congress creates the United States House Committee on Appropriations and the Committee on Banking and Commerce, reducing the tasks of the House Committee on Ways and Means.
December 17 – Léopold II becomes King of the Belgians, following the death (on December 10) of his father, King Leopold I.
December 18 – Secretary Seward declares the Thirteenth Amendment to the United States Constitution ratified by three-quarters of the states (including those in secession) as of December 6; slavery is legally outlawed in the last two slave states of Kentucky and Delaware and the remaining 45,000 slaves are freed.
December 21 – The Kappa Alpha Order is founded at Washington College, Lexington, Virginia.
December 24 – Jonathan Shank and Barry Ownby form the Ku Klux Klan in the American South, to resist Reconstruction and intimidate "carpetbaggers" and "scalawags", as well as to repress the freedpeople.
A forest fire near Silverton, Oregon destroys about one million acres (4,000 km²) of timber.
The National Temperance Society and Publishing House is founded by James Black in the U.S.
January 5 – Julio Garavito Armero, Colombian astronomer (d. 1920)
January 9 – Leo Ditrichstein, Austrian born stage actor and playwright (d. 1928)
January 10 – Mary Ingalls, blind older sister of American author Laura Ingalls Wilder (d. 1928)
January 19 – Valentin Serov, Russian painter, mainly of portraits (d. 1911)
January 27 – Nikolai Pokrovsky, Russian politician and last foreign minister of the Russian Empire (d. 1930)
Verina Morton Jones, African American physician, suffragist and clubwoman (d. 1943)
Lala Lajpat Rai "The Lion of Punjab", a leader of the Indian independence movement (d. 1928)
Kaarlo Juho Ståhlberg, President of Finland (d. 1952)
February 4 – Ernest Hanbury Hankin, English bacteriologist and naturalist (d. 1939)
February 9 – Beatrice Stella Tanner, later Mrs. Patrick Campbell, English theatre actress and producer (d. 1940)
February 28 – Alexander Henderson, American businessman (d. 1925)
February 12 – Kazimierz Tetmajer, Polish writer (d. 1940)
February 17 – Ernst Troeltsch, German theologian (d. 1923).
February 19 – Sven Hedin, Swedish scientist and explorer (d. 1952)
February 21 – John Haden Badley, English author and educator (d. 1967)
February 28 – Wilfred Grenfell, English medical missionary to Newfoundland and Labrador (d. 1940)
March 1 – Elma Danielsson, Swedish socialist and journalist (d. 1936)
March 10 – Tan Sitong, Chinese reformist leader (d. 1898)
March 15 – Edith Maude Eaton, English-born writer (d. 1914)
March 19 – William Morton Wheeler, American entomologist (d. 1937)
March 30 – Heinrich Rubens, German physicist (d. 1922)
April 1 – Richard Adolf Zsigmondy, Austrian-born chemist, Nobel Prize laureate (d. 1929)
April 2 – Gyorche Petrov, Macedonian and Bulgarian revolutionary (d. 1921)
Laurence Hope, English poet (d. 1904)
Erich Ludendorff, German general (d. 1937)
Charles Proteus Steinmetz, German-American engineer and electrician (d. 1923)
April 14 – Alfred Hoare Powell, English Arts and Crafts architect, and designer and painter of pottery (d. 1960)
Vital Brazil, Brazilian physician and immunologist (d. 1950)
Charles W. Woodworth, American entomologist (d. 1940)
May 2 – Clyde Fitch, American dramatist (d. 1909)
May 3 – Henry Francis Bryan, governor of American Samoa (d. 1944)
John Mott, American YMCA leader, recipient of the Nobel Peace Prize (d. 1955)
Pieter Zeeman, Dutch physicist, Nobel Prize laureate (d. 1943)
May 26 – Robert W. Chambers, American artist (d. 1933)
June 2 – George Lohmann, English cricketer (d. 1901)
June 3 – King George V of the United Kingdom (d. 1936)
Albéric Magnard, French composer (d. 1914)
Carl Nielsen, Danish composer (d. 1931)
June 13 – William Butler Yeats, Irish writer, Nobel Prize laureate (d. 1939)
Alfred Hugenberg, German businessman and politician (d. 1951)
May Whitty, British stage & screen actress (d. 1948)
June 21 – Otto Frank (physiologist), German doctor (d. 1944)
June 26 – Bernard Berenson, American art historian (d. 1959)
July 13 – Gérard Encausse, French occultist (d. 1916)
July 15 – Alfred Harmsworth, 1st Viscount Northcliffe, Irish-born, British publisher; founder of the Daily Mail and Daily Mirror (d.1922)
Max Heindel, Danish-born Christian occultist, astrologer, and mystic (d. 1919)
Edward Terry Sanford, Associate Justice of the Supreme Court of the United States (d. 1930)
July 26 – Philipp Scheidemann, Chancellor of Germany (d. 1939)
Irving Babbitt, American literary critic (d. 1933)
John Radecki, Australian stained glass artist (d. 1955)
August 10 – Alexander Glazunov, Russian composer (d. 1936)
August 15 – Usui Mikao, Japanese founder of reiki (d. 1926)
August 20 – Bernard Tancred, South African cricketer (d. 1911)
August 24 – King Ferdinand I of Romania (d. 1927)
August 26 – Arthur James Arnot, Scottish-Australian electrical engineer and inventor (d. 1946)
James Henry Breasted, American Egyptologist (d. 1935)
Charles G. Dawes, 30th Vice President of the United States, recipient of the Nobel Peace Prize (d. 1951)
September 11 – Rainis, Latvian poet and playwright (d. 1929)
September 13 – William Birdwood, 1st Baron Birdwood, British field marshal (d. 1951)
September 24 – Mollie McConnell, American actress (d. 1920)
September 26 – Mary Russell, Duchess of Bedford, English aviator and ornithologist (d. 1937)
September 27 – Ezra Fitch, American businessman and co-founder of Abercrombie & Fitch (d. 1930)
October 1 – Paul Dukas, French composer (d. 1935)
October 9 – Arthur Hayes-Sadler, British admiral (d. 1952)
October 12 – Arthur Harden, English chemist, Nobel Prize laureate (d. 1940)
October 15 – Charles W. Clark, American baritone (d. 1925)
October 17 – James Rudolph Garfield, U.S. politician (d. 1950)
Charles James Briggs, British general (d. 1941)
Raymond Hitchcock, American actor (d. 1929)
October 26 – Benjamin Guggenheim, American businessman (d. 1912)
October 27 – Tinsley Lindley, English footballer (d. 1940)
Warren G. Harding, 29th President of the United States (d. 1923)
Paul Olaf Bodding, Norwegian missionary to India and creator of Santali Latin alphabet (d. 1938)
December 8 – Jean Sibelius, Finnish composer (d. 1957)
December 16 – Olavo Bilac, Brazilian poet (d. 1918)
December 19 – Minnie Maddern Fiske, American stage actress (d. 1932)
December 20 – Elsie de Wolfe, American socialite and interior decorator (d. 1950)
December 23 – Albrecht, Duke of Württemberg, German field marshal (d. 1939)
Evangeline Booth, 4th General of The Salvation Army (d. 1950)
Fay Templeton, Broadway musical comedy star (d. 1939)
December 28 – Félix Vallotton, Swiss painter and printmaker (d. 1925)
December 30 – Rudyard Kipling, Indian-born English writer, Nobel Prize laureate (d. 1936)
undated – Pauline Schmidt, Danish magician (d. 1944)
January 14 – Marie-Anne Libert, Belgian botanist (b. 1782)
January 19 – Pierre-Joseph Proudhon, French philosopher and anarchist (b. 1809)
January 28 – Felice Romani, poet and librettist (b. 1788)
February 6 – Isabella Beeton, British cook and expert on household management (b. 1836)
March 1 – Anna Pavlovna of Russia, queen consort of the Netherlands (b. 1795)
March 20 – Yamanami Keisuke, samurai (b. 1833)
March 30 – Alexander Dukhnovich, priest, writer and social activist (b. 1803
John Milton, Governor of Florida (b. 1807)
Giuditta Pasta, Italian soprano (b. 1798)
April 2 – A. P. Hill, American Confederate general (b. 1825)
April 13 – Achille Valenciennes, French zoologist (b. 1794)
April 15 – Abraham Lincoln, 16th President of the United States (b. 1809)
April 18 – Léon Jean Marie Dufour, French medical doctor and naturalist (b. 1780)
April 24 – Nicholas Alexandrovich, Tsarevich of Russia (b. 1843)
April 26 – John Wilkes Booth, American actor and assassin of Abraham Lincoln (b. 1838)
April 28 – Sir Samuel Cunard, Canadian businessman, founder of the Cunard Line (b. 1787)
July – Dimitris Plapoutas, Greek military leader (b. 1786)
July 6 – Princess Sophie of Sweden, Grand Duchess of Baden (b. 1801)
July 7 – The Lincoln assassination conspirators (executed)
Lewis Powell (b. 1844)
David Herold (b. 1842)
George Atzerodt (b. 1835)
Mary Surratt (b. 1823)
July 25 – James Barry, British military surgeon (b. 1795)
August 4 – Percival Drayton, United States Navy officer (b. 1812)
August 12 – William Jackson Hooker, English botanist (b. 1785)
August 13 – Ignaz Semmelweis, Hungarian physician (b. 1818)
August 27 – Thomas Chandler Haliburton, Canadian author (b. 1796)
August 29 – Robert Remak, German embryologist, physiologist, and neurologist, (b. 1815)
September 2 – William Rowan Hamilton, Irish mathematician (b. 1805)
September 10 – Maria Silfvan, Finnish actor (b. 1802)
October 16 – Andrés Bello, Venezuelan poet, lawmaker, teacher, philosopher and sociologist (b. 1781)
October 18 – Henry John Temple, 3rd Viscount Palmerston, Prime Minister of the United Kingdom (b. 1784)
November 10 – Henry Wirz, Confederate military officer and prisoner-of-war camp commander (executed) (b. 1823)
November 12 – Elizabeth Gaskell, British novelist and biographer (b. 1810)
November 28 – William Machin Stairs, Canadian businessman and statesman (b. 1789)
December 6 – Sebastián Iradier, Spanish composer (b. 1809)
December 10 – King Leopold I of Belgium (b. 1790)
December 14 – Johan Georg Forchhammer, geologist (b. 1794)
December 17 – Luigi Ciacchi, Italian cardinal (b. 1788)
1865 (MDCCCLXV) was a common year starting on Sunday (dominical letter A) of the Gregorian calendar and a common year starting on Friday (dominical letter C) of the Julian calendar, the 1865th year of the Common Era (CE) and Anno Domini (AD) designations, the 865th year of the 2nd millennium, the 65th year of the 19th century, and the 6th year of the 1860s decade. As of the start of 1865, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.