| 1810–1859 | USA [agriculture] | US cotton production, the vast majority of which is grown in the southern states, rises from 171,000 bales in 1810 to just under 5.4 million in 1859. |
| 1840–1860 | world [plagues and epidemics] | A cholera pandemic kills millions of people worldwide. |
| 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. |
| 1851–1860 | world [photography] | Photographic exposure times become short enough to capture movement. |
| 1851–1860 | USA, UK [statistics and demography] | Emigration to the USA from Britain is 423,964, and from Ireland, 914,119. |
| 1855 | France [physiology] | The French physiologist Claude Bernard discovers that ductless glands produce hormones, which he calls ‘internal secretions’. |
| 1855 | Germany [physiology] | The German biologist Rudolf Virchow discovers that ‘every cell is derived from a cell’ – the principle of cell division. |
| 1855 | UK [magazines] | British publisher Samuel Orchart Beeton launches the Boy's Own Magazine. The first children's magazine to be concerned with entertainment rather than education, its main subjects are adventure stories and sports, and it is very successful. |
| 1855 | Austrian Empire [materials] | Austrian chemist Franz Köller adds tungsten to steel to make tungsten steel. It is harder than normal steel and tools made from the alloy last up to six times as long as others. |
| 1855 | USA [poetry] | The US writer Henry Wadsworth Longfellow publishes his long narrative poem The Song of Hiawatha, one of his best-known works. |
| 1855 | England [poetry] | The English poet Alfred, Lord Tennyson, publishes Maud and Other Poems. |
| 1855 | England [poetry] | The English poet Robert Browning publishes his collection of poetry Men and Women. |
| 1855 | England [psychology] | The English social scientist Herbert Spencer publishes Principles of Psychology, in which, several years before Charles Darwin's The Origin of Species, he sets out a theory of evolution. |
| 1855 | England [fiction] | The English writer Anthony Trollope publishes his novel The Warden. |
| 1855 | USA, Canada [canals] | The Sault Ste Marie Canal, between lakes Superior and Huron, is completed. It bypasses the St Mary's River rapids and makes the Great Lakes a navigable waterway. |
| 1855 | UK [chemistry] | British chemist Alexander Parkes invents the first synthetic plastic. |
| March 1855 | USA [elections] | Violence and fraud mar Kansas' territorial election, as pro-slavery partisans from Missouri cross into Kansas to swell the ranks of pro-slavery legislators. Despite evidence of fraud, the Pierce administration endorses the election results. |
| 2 March 1855 | Russian Empire [political events] | Following the death of the reactionary tsar Nicholas I of Russia, he is succeeded by the more moderate Alexander II. |
| 31 March 1855 | England [births and deaths] | Charlotte Brontë, English novelist who wrote Jane Eyre (1847), dies in Haworth, Yorkshire (now West Yorkshire), England (38). |
| 21 April 1855 | USA [other structures] | The first bridge across the Mississippi, between Rock Island, Illinois, and Davenport, Iowa, opens to rail traffic. |
| 29 June 1855 | UK [newspapers] | The Daily Telegraph newspaper is launched in Britain. |
| 16 July 1855 | UK, Australia [law and government] | The British Parliament establishes responsible government throughout the Australian states, except for Western Australia. |
| 11 September 1855 | UK, France, Russian Empire [Crimean War (1854–56)] | British and French forces enter the Crimean city of Sevastopol after the besieged Russians within capitulate. |
| 3 November 1855 - 20 May 1856 | Africa [exploration] | Scottish missionary and explorer David Livingstone completes his crossing of the African continent by travelling eastwards from Linyanti on the River Zambezi to Quelimane in Portuguese East Africa, visiting and naming the Victoria Falls (17 November 1855) on the way. |
