|Centuries:||18th century – 19th century – 20th century|
|Decades:||1820s 1830s 1840s – 1850s – 1860s 1870s 1880s|
|Years:||1848 1849 1850 – 1851 – 1852 1853 1854|
- January 23 – The flip of a coin determines whether a new city in Oregon is named after Boston, Massachusetts, or Portland, Maine, with Portland winning.
- March 1 – Victor Hugo gives speech at the French national assembly and uses the phrase United States of Europe several times
- March 27 – First reported case of white men seeing Yosemite Valley.
- March 30 – A population census was taken of all people living in the United Kingdom.
- May 1 – The Great Exhibition of the Works of Industry of All Nations in the Crystal Palace, Hyde Park, London is opened by Queen Victoria. It runs until October 18.
- May 15 – Rama IV is crowed King of Thailand.
- July – The immortal game, a famous chess game, is played.
- July 1 – Colony of Victoria separates from New South Wales.
- July 29 – Annibale de Gasparis, in Naples, Italy discovers asteroid 15 Eunomia.
- August 22 – The yacht America wins the first America's Cup race (see Yachting).
- October 18 – The Great Exhibition in London is closed.
- November 13 – The Denny Party lands at Alki Point, the first settlers of what will become Seattle, Washington.
- December 2 – Louis Napoleon, president of France, dissolves French National Assembly and declares a new constitution to extend his term. Later he declares himself as an emperor Napoleon III. End of the Second Republic.
- December 24 – The Library of Congress burns.
- December 29 – The first YMCA opens, in Boston, Massachusetts.
- January 17 – A. B. Frost, American illustrator (d. 1928)
- January 19 – Jacobus Kapteyn, Dutch astronomer (d. 1922)
- February 8 – Kate Chopin, American writer (d. 1904)
- March 27 – Vincent d'Indy, French composer and teacher (d. 1931)
- April 21 – Charles Barrois, French geologist (d. 1939)
- May 6 – Aristide Bruant, French cabaret singer and comedian (d. 1925)
- May 20 – Emil Berliner, telephone and recording pioneer (d. 1929)
- August 14 – Doc Holliday, American gambler and gunfighter (d. 1887)
- October 2 – Ferdinand Foch, French commander of allied forces in World War I (d. 1929)
- October 31 – Princess Louise of Sweden
- Robert Abbe, American surgeon (d. 1928)
- Ruperto Chapí, Spanish zarzuelist
- Tom Morris, Jr., Scottish golfer (d. 1875)