1854 (MDCCCLIV) 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 1854th year of the Common Era (CE) and Anno Domini (AD) designations, the 854th year of the 2nd millennium, the 54th year of the 19th century, and the 5th year of the 1850s decade. Note that the Julian day for 1854 is 12 calendar days difference, which continued to be used from 1582 until the complete conversion of the Gregorian calendar was entirely done in 1929.
- January 3 –Charles Dickens commences writing the novel Hard Times.
- January 6 – The fictional detective Sherlock Holmes is born.
- January 9 –The Teutonia Männerchor in Pittsburgh, U.S.A. is founded to promote German culture.
- January 20 –The North Carolina General Assembly in the United States charters the Atlantic and North Carolina Railroad to run from Goldsboro through New Bern to the newly created seaport of Morehead City near Beaufort.
- January 21 –The iron clipper RMS Tayleur runs aground off the east coast of Ireland on her maiden voyage out of Liverpool bound for Australia with the loss of at least 300 of around 650 on board.
- February 11 –Major streets are lit by coal gas for the first time.
- February 13 –Mexican troops force William Walker and his troops to retreat to Sonora.
- February 14 –Texas is linked by telegraph with the rest of the United States, when a connection between New Orleans and Marshall, Texas is completed.
- February 17 –The British recognize the independence of the Orange Free State in Southern Africa; its official independence is declared 6 days later.
- February 27 –Britain sends Russia an ultimatum to withdraw from two Romanian provinces it has conquered, Moldavia and Wallachia.
- February 28 –The Republican Party (United States) is founded in Ripon, Wisconsin.
- March – The British East India Company annexes Jhansi State in India under the doctrine of lapse.
- March 1 –German psychologist Friedrich Eduard Beneke disappears; 2 years later his remains are found in the canal near Charlottenburg.
- March 3 –Australia's first telegraph line, linking Melbourne and Williamstown, opens.
- March 11 –A Royal Navy fleet sails from Britain under Vice Admiral Sir Charles Napier.
- March 20 –The Boston Public Library opens to the public.
- March 24 –In Venezuela, slavery was abolished
- March 27 –Crimean War: The United Kingdom declares war on Russia.
- March 28 –France declares war on Russia.
- March 31 –Commodore Matthew C. Perry of the United States Navy signs the Convention of Kanagawa with the Japanese government (the Tokugawa shogunate), opening the ports of Shimoda and Hakodate to American trade (see History of Japan).
- April 1 –Hard Times begins serialisation in Charles Dickens' magazine, Household Words.
- April 16 –The United States packet ship Powhattan is wrecked off the New Jersey shore with more than 200 victims.
- May 18 –The Catholic University of Ireland (forerunner of University College Dublin) is founded.
- May 27 –Taiping Rebellion: United States diplomatic minister Robert McLane arrives at the Heavenly Capital aboard the American warship USS Susquehanna.
- May 30 –The Kansas–Nebraska Act becomes law (replacing the Missouri Compromise of 1820), creating the Kansas Territory and the Nebraska Territory, west of the State of Missouri and the State of Iowa. The Kansas–Nebraska Act also establishes that these two new Territories will decide either to allow or disallow slavery depending on balloting by their residents. These areas would have been strictly "free territory" under the Missouri Compromise, which allowed slavery in the State of Missouri but disallowed it in any other new state north of latitude 36° 30', which forms most of the southern boundary of Missouri. This prohibition of slavery extended all the way from the western boundary of Missouri to the Pacific Ocean.
- June –The Grand Excursion takes prominent Eastern United States inhabitants from Chicago to Rock Island, Illinois by railroad, then up the Mississippi River to Saint Paul, Minnesota by steamboat.
- June 10 –The first class of the United States Naval Academy graduates at Annapolis, Maryland.
- June 21 –Battle of Bomarsund in the Åland Islands off the coast of Finland. British Royal Navy seaman's mate Charles D. Lucas throws a live Russian artillery shell overboard by hand before it explodes, for which he is awarded the first Victoria Cross in 1857.
- July 4 –James Ambrose Cutting takes out the first of his three United States patents for improvements to the wet plate collodion process (Ambrotype photography).
- July 6
- July 7 –Bombay Spinning and Weaving Company established as the first cotton mill in India by Cowasjee Nanabhoy Davar and associates.
- July 17 –Bienio progresista: Revolutionary coup in Spain.
- July 19 –Wood's despatch is sent by Charles Wood, 1st Viscount Halifax to Lord Dalhousie, Governor General of India, proposing radical improvements to the Indian educational system.
- August 9 –Johann succeeds to the throne of Saxony on the death of his brother.
- August 16 –Battle of Bomarsund: Russian troops in the island of Bomarsund in the Åland Islands surrender to French–British troops.
- August 27 –English lawyer Alfred Wills and party set out for the first ascent of the Wetterhorn in Switzerland, regarded as the start of the "golden age of alpinism".
- August 31–September 8 – An epidemic of cholera in London kills 10,000. Dr John Snow traces the source of one outbreak (that killed 500) to a single water pump, validating his theory that cholera is water-borne, and forming the starting point for epidemiology.
- September 20 –Crimean War: Battle of Alma – The French–British alliance wins the first major land engagement of the war.
- October 1 –The watch company founded in 1850 in Roxbury, Massachusetts by Aaron Lufkin Dennison relocates to Waltham to become the Waltham Watch Company, pioneer in the American system of watch manufacturing.
- October 9–11 – United States diplomats in Europe meet and draft the Ostend Manifesto, setting out a rationale for the U.S. to acquire Cuba from Spain.
- October 6 –The great fire of Newcastle and Gateshead in England is ignited by a spectacular explosion.
- October 17 –The Age newspaper is founded in Melbourne, Australia.
- October 25 –Crimean War – Battle of Balaclava: The allies gain an overall victory, except for the disastrous cavalry Charge of the Light Brigade, from which only 200 of 700 men survive.
- November –Florence Nightingale and her team of 38 trained volunteer nurses, having set out on October 21 from England, arrive at Selimiye Barracks in Scutari in the Ottoman Empire to care for British Army troops invalided from the Crimean War.
- November 5 –Crimean War – Battle of Inkerman: The Russians are defeated.
- November 17 –In Egypt, the Suez Canal company is formed.
- December 3 –The Eureka Stockade Miners' Rebellion breaks out in Ballarat, Victoria (Australia).
- December 8 –Pope Pius IX in the apostolic constitution Ineffabilis Deus defines ex Cathedra the dogma of Immaculate Conception, which holds that the Blessed Virgin Mary was conceived without original sin.
- Ignacy Łukasiewicz drills the world's first oil well in Poland, in Bóbrka near Krosno County.
- Professor Benjamin Silliman of Yale University is the first person to fractionate petroleum into its individual components by distillation.
- The Icelandic trade is opened to merchants other than Danes.
- Manchester is granted city status in the United Kingdom.
- A Russian fort is established at the modern-day site of Almaty.
- The French fashion label Louis Vuitton is founded.
- The Waterbury Clock Company is founded in Waterbury, Connecticut, the predecessor of Timex Group USA in timepiece manufacturing.
- January 1 – James George Frazer, Scottish social anthropologist (d. 1941)
- January 8 or January 11 – Samuel Liddell MacGregor Mathers, British occultist (d. 1918)
- January 12 –David Macpherson, Canadian-born American civil engineer (d. 1927)
- February 9 –Edward Carson, Irish Unionist MP and Barrister (d. 1935)
- February 16 –Charles Webster Leadbeater, British theosopher (d. 1934)
- February 17 –Friedrich Alfred Krupp, German industrialist (d. 1902)
- March 4 – Tomás António Garcia Rosado, Portuguese general (d. 1937)
- March 14 – Paul Ehrlich, German physician and scientist (d. 1915)
- March 15 – Emil von Behring, German physiologist, 1901 Nobel Prize in Physiology or Medicine (d. 1917)
- April 17 –Paul von Rennenkampf, Russian general (d. 1918)
- April 28 –Hertha Marks Ayrton, English engineer, mathematician and inventor (d. 1923)
- April 29 –Henri Poincaré, French mathematician and physicist (d. 1912)
- May 11 –Albion Woodbury Small, American sociologist (d. 1926)
- May 24 –John Riley Banister, American law officer and Texas Ranger (d. 1918)
- June 8 –Douglas Cameron, Canadian politician (d. 1921)
- June 14 –Dave Rudabaugh, American outlaw and gunfighter (d. 1886)
- June 17 –Robert Kekewich, British general (d. 1914)
- June 26 –Robert Borden, 8th Prime Minister of Canada (d. 1937)
- July 3 –Leoš Janáček, Czech composer (d. 1928)
- July 7 –Nikolai Alexandrovich Morozov, Russian poet, scientist and revolutionary (d.1946)
- July 12 –George Eastman, American photographic inventor (Kodak) (suicide 1932)
- July 27 –Takahashi Korekiyo, Prime Minister of Japan (d. 1936)
- August 2 –Milan I of Serbia (d. 1901)
- August 23 –Moritz Moszkowski, Polish/German composer (d. 1925)
- September 1 –Engelbert Humperdinck, German composer (d. 1921)
- September 2 –Paul Marie Eugène Vieille, French chemist and gunsmith (d. 1934)
- September 3 –Anna Sandström, Swedish social reformer (d. 1931)
- September 6 –Georges Picquart, French general and Minister of War (d. 1914)
- October 3 –William C. Gorgas, American physician and Surgeon General (d. 1920)
- October 7 –Christiaan de Wet, Boer general, rebel leader, and politician (d. 1922)
- October 16
- October 20 –Arthur Rimbaud, French poet (d. 1891)
- October 26 –C. W. Post, American cereal manufacturer (d. 1914)
- November 5 –Paul Sabatier, French chemist, Nobel Prize laureate (d. 1941)
- November 6 –John Philip Sousa, American composer and conductor (Stars and Stripes Forever) (d. 1932)
- November 13 –George Whitefield Chadwick, American composer (d. 1931)
- November 17 –Hubert Lyautey, Marshal of France (d. 1934)
- December 16 –Austin M. Knight, American admiral (d. 1927)
- November 21 –Pope Benedict XV (d. 1922)
- December 22 –Takamine Jōkichi, Japanese chemist (d. 1922)
- December 23 –Victoriano Huerta, President of Mexico (d. 1916)
- December 24 –Thomas Stevens, English cyclist (d. 1935)
- January 8 –William Beresford, 1st Viscount Beresford, British general and politician (b. 1768)
- February 17 –John Martin, English painter (b. 1789)
- March 6 –Charles Vane, 3rd Marquess of Londonderry (b. 1778)
- March 11 –Willard Richards, American religious leader (b. 1804)
- March 13 –Thomas Talfourd, English jurist (b. 1795)
- March 19 –William Pope Duval, first civilian governor of Florida Territory (b. 1784)
- March 27
- April – Domingo Eyzaguirre, Chilean philanthropist (b. 1775)
- April 11 –Karl Adolph von Basedow, German physician (b. 1799)
- April 15 –Arthur Aikin, English chemist and mineralogist (b. 1773)
- April 29 –Henry Paget, 1st Marquess of Anglesey, British general (b. 1768)
- July 6 –Georg Ohm, German physicist
- July 16 –Abbas I, Pasha of Egypt (b. 1813)
- July 31 –Samuel Wilson, American thought to be the real-life basis for Uncle Sam (b. 1766)
- August – Conquering Bear, Lakota chief
- August 2 –Heinrich Clauren (b. 1771)
- August 9 –Frederick Augustus II of Saxony (b. 1797)
- August 20 –Friedrich Wilhelm Joseph Schelling, German philosopher (b. 1775)
- August 21 –Thomas Clayton, American lawyer and politician (b. 1777)
- September 8 –Angelo Mai, Italian cardinal and philologist (b. 1782)
- September 12 –Jarvis W. Pike, former Mayor of Columbus, Ohio
- October 26 –Therese of Saxe-Hildburghausen, queen consort of Bavaria (b. 1792)
- November 2 –George Mogridge (Old Humphrey), British writer and poet (b.1787)
- November 3 –Maxim Gauci, Maltese lithographer (b. 1774)
- November 25 –John Gibson Lockhart, Scottish writer (b. 1794)
- December 9 –Almeida Garrett, Portuguese writer (b. 1799)
- December 15 –Kamehameha III, King of Hawaii (b. c. 1814)