- Jan 1 City of Glasgow steamer inaugurates Philadelphia-Liverpool line
- Jan 15 General Mariano Arista replaces Mexican President José Joaquín de Herrera
- Feb 11 Inaugural 1st-class cricket match in Australia; Tasmania v Victoria in Launceston; Tasmania wins by 3 wickets
- Feb 12 Edward Hargraves and three other men discover gold at Ophir, New South Wales, beginning Australia's first gold rush 
- Feb 15 Black abolitionists invade Boston courtroom rescuing a fugitive slave
- Feb 26 13th Grand National: Terry Abbott wins aboard Irish stallion Abd-El-Kader at 7/1; first dual winner and first to win back-to-back
- Mar 3 Congress authorizes smallest US silver coin (3 cent piece)
- Mar 7 Poll tax levied on Russo-Polish Jews entering Austrian Galicia ends
- Mar 25 Yosemite Valley discovery made public by Major James D. Savage and Captain John Boling after being shown by Indian guides in California
- Apr 15 Earl G Andressy sentenced to death in Hungary
- Apr 23 Canada issues its 1st postage stamps
- May 1 First public flushing toilets the 'Monkey Closets' unveiled by George Jennings as part of The Great Exhibition at Hyde Park, London, costing one penny
- May 1 Great Exhibition opens in the Crystal Palace, at Hyde Park, London
- May 3 Sixth major fire in San Francisco destroys 1500-2000 buildings
- May 6 Dr John Gorrie patents a "refrigeration machine"
- May 6 Linus Yale Jr. patents the Yale cylinder lock
- May 6 New slave regulations go into effect in Suriname
- May 6 San Francisco Chamber of Commerce starts
- May 15 King Mongkut [Rama IV or Phra Chomklao Chaoyuhua] crowned in Siam (Thailand)
- May 18 Amsterdam-Nieuwediep telegraph connection linked
Conference of Interest
May 29 Sojourner Truth addresses 1st Black Women's Rights Convention in Akron, Ohio
War Breaks Out Behind Uncle Tom's Cabin
Jun 5 Anti-slavery novel "Uncle Tom's Cabin" by Harriet Beecher Stowe first published in serial form in "The National Era"
- Jun 9 San Francisco Committee of Vigilance forms (1st time)
- Jun 15 Jacob Fussell, Baltimore dairyman, sets up 1st ice-cream factory
- Jun 22 Fire destroys part of San Francisco, including City Hall and Jenny Lind Theatre, city's seventh fire in 2 years
- Jun 30 Battle of Viervoet: Basotho forces led by Moshoeshoe defeat the British over the British imposed Walden line
- Jul 13 John F Loudon discovers tin on East Indian Island of Billiton
- Jul 23 Treaty of Traverse des Sioux signed by Sioux Indians and US
Light and Air For All – With No Charge!
Jul 24 The long hated Window Tax is abolished in the United Kingdom
- Jul 28 Total solar eclipse captured on a daguerreotype photograph
- Jul 29 Annibale de Gasparis discovers asteroid 15 Eunomia
- Aug 12 American inventor Isaac Singer patents the sewing machine
- Aug 22 100 Guineas Cup is raced around Isle of Wight; US schooner 'America' beats British cutter 'Aurora' by 24 minutes; first competition for the America's Cup yachting trophy
- Aug 22 Gold fields discovered in Australia
- Sep 15 Saint Joseph's University is founded in Philadelphia, Pennsylvania
- Sep 18 New York Times starts publishing (2 cents a copy)
- Sep 22 City of Des Moines, Iowa incorporated as Fort Des Moines
- Oct 1 1st Hawaiian stamps issued
- Oct 2 The pasilalinic-sympathetic compass(a contraption built to test the pseudo-scientific hypothesis that snails create a permanent telepathic link when they mate) is demonstrated but proves to be a fake.
- Oct 24 William Lassell discovers Ariel & Umbriel, satellites of Uranus
- Oct 30 Alfred de Musset's "Bettine" premieres in Paris
- Nov 9 Kentucky marshals abduct abolitionist minister Calvin Fairbank from Jeffersonville, Indiana, and take him to Kentucky to stand trial for helping a slave escape.
- Nov 11 Alvan Clark patents telescope
- Nov 13 1st meeting of anti-revolutionary "Netherlands & Orange"
- Nov 13 Telegraph connection between London-Paris linked
- Nov 13 The Denny Party lands at Alki Point, the first settlers of what would become Seattle, Washington
Nov 14 "Moby-Dick" by Herman Melville first published by Harper and Brothers in the US
- Nov 22 Opera "La Perle Du Brésil" is produced (Paris)
- Dec 2 French President Charles Louis Bonaparte in a Coup d'etat overthrows the Second Republic establishing himself as Emperor.
- Dec 4 President Louis Napoleon Boaparte's forces crush an attempted coup d'etat in France
- Dec 9 1st Young Men's Christian Association in North America set up in Montreal
- Dec 22 The first freight train is operated in Roorkee, India.
- Dec 24 Fire devastates US Library of Congress in Washington, destroys 35,000 volumes
- Dec 29 1st American Young Men's Christian Association (YMCA) chapter opened in Boston, Massachusetts