| 1845–1958 | Germany [earth sciences] | German naturalist and explorer Alexander von Humboldt lays the basis of modern geography with the publication of Kosmos/Cosmos, in which he arranges geographic knowledge in a systematic fashion. |
| 1861–1865 | USA [economic conditions] | The USA, or the North, has a booming economy during the Civil War as production and profits soar. There is inflation, too; prices rise 117% and wages rise just 43%. |
| 1861–1870 | USA, UK, Ireland [statistics and demography] | Emigration to the USA from Britain totals 606,896; from Ireland it is 435,779. |
| 1865 | Sweden [technology] | The Swedish inventor Alfred Nobel invents the blasting cap. Used to detonate nitroglycerine safely and dependably, it expands the use of explosives in industry. |
| 1865 | UK [legislation] | The British Parliament passes the British Locomotives on Highways Act, or ‘Red Flag Act’. It reduces the speed limit for steam-powered carriages to two miles per hour in cities and four in the country, and requires men on foot carrying red flags to precede them. It stifles further development of steam carriages and cars in Britain. |
| 1865 | UK, Australia [crime and punishment] | The authorities in Britain's Australian colonies refuse to accept further shipments of transported British criminals. As a result, longer, harsher sentences are introduced in Britain. |
| 1865 | USA [media and communication] | US financier Cyrus West Field and Scottish physicist William Thomson, Lord Kelvin, use Isambard Kingdom Brunel's steamship the Great Eastern to begin laying the first successful transatlantic telegraph cable. |
| 1865 | Germany [opera] | The opera Tristan und Isolde/Tristan and Isolde by the German composer Richard Wagner is first performed, in Munich, Germany. Among its best-known parts is the Liebestod sung by Isolde. |
| 1865 | Hungary [orchestral music] | The Hungarian composer Franz Liszt completes his orchestral work Rákóczymarsch/Rákóczy March. |
| 1865 | France [physiology] | French physiologist Claude Bernard develops the concept of homeostasis when he notes that ‘all the vital mechanisms, varied as they are, have only one object: that of preserving constant the conditions of life’. |
| 1865 | Germany [chemistry] | German chemist Friedrich August Kekulé von Stradonitz proposes the molecular structure of benzene. |
| 27 January 1865 | Spain, Peru [treaties] | A treaty between Spain and Peru recognizes the independence of the former Spanish colony, following ongoing friction since the latter's cession. |
| 18 February 1865 | USA, Confederate States of America [American Civil War (1861–65)] | The Confederate port of Charleston, South Carolina, besieged by the US Navy since 1861, surrenders. |
| 18 March 1865 | Paraguay, Argentina, Brazil, Uruguay [wars] | The dictator of Paraguay, President Francisco Solano López, seizes Argentine territory, provoking a war against Argentina, Brazil, and Uruguay. |
| 9 April 1865 | USA, Confederate States of America [American Civil War (1861–65)] | The Confederate Army of Northern Virginia under Robert E Lee surrenders to Union general Ulysses S Grant at Appomattox Courthouse, Virginia. |
| 15 April 1865 | USA [births and deaths] | Abraham Lincoln, 16th president of the USA 1861–65, a Republican, dies in Washington, DC, and is succeeded by Vice-President Andrew Johnson (56). |
| 26 May 1865 | USA, Confederate States of America [American Civil War (1861–65)] | The surrender of the last Confederate army at Shreveport, near New Orleans, Louisiana, ends the American Civil War. |
| 13 June 1865 | Ireland [births and deaths] | W(illiam) B(utler) Yeats, Irish poet, dramatist, and nationalist, born in Sandymount, Dublin, Ireland (–1939). |
| 2 July 1865 | UK [charities] | William and Catherine Booth launch their Christian Mission in Britain, which they will later name the Salvation Army. |
| 14 August 1865 | Austrian Empire, Prussia, Denmark [treaties] | The Convention of Gastein temporarily resolves the question of the administration of the duchies of Schleswig and Holstein (ceded to Austria and Prussia by Denmark). Austria receives Holstein and Prussia obtains Schleswig and the port city of Kiel, while purchasing the duchy of Lauenburg. |
| 26 September 1865 | New Zealand, UK [legislation] | A Native Rights Act in New Zealand recognizes the Maori people as natural-born subjects of Queen Victoria of Great Britain, and institutes a land court to hear their grievances against colonial settlers who have dispossessd them of their lands. |
| 18 October 1865 | England [political events] | Henry Temple, Viscount Palmerston, British statesman, prime minister 1855–58 and 1859–65, a Liberal, dies in Brocket Hall, Hertfordshire, England (80). |
| 29 October 1865 | UK [administration] | The Liberal politician Lord John Russell becomes prime minister of Great Britain. |
| 10 December 1865 | Belgium [political events] | King Leopold I of Belgium dies and is succeeded by his son, Leopold II. |
| 12 December 1865 | Sweden [legislation] | A new constitution in Sweden abolishes the traditional four estates and replaces them with two chambers, following long-standing demands for political reform. |
| 24 December 1865 | USA [civil rights] | Former Confederate cavalry commander Nathan Bedford Forrest founds the Ku Klux Klan, allegedly as a social club for Confederate veterans and their families. |
| 30 December 1865 | England, India [births and deaths] | Rudyard Kipling, English novelist, short-story writer, and poet, born in Bombay (now Mumbai), India (–1936). |
