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1869 (MDCCCLXIX) was a common year starting on Friday of the Gregorian calendar and a common year starting on Wednesday of the Julian calendar, the 1869th year of the Common Era (CE) and Anno Domini (AD) designations, the 869th year of the 2nd millennium, the 69th year of the 19th century, and the 10th and last year of the 1860s decade. As of the start of 1869, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.
- January 3 – Abdur Rahman Khan is defeated at Tinah Khan, and exiled from Afghanistan.
- January 5 – Scotland's oldest professional football team, Kilmarnock F.C., is founded.
- January 20 – Elizabeth Cady Stanton is the first woman to testify before the United States Congress.
- January 21 – The P.E.O. Sisterhood, a philanthropic educational organization for women, is founded at Iowa Wesleyan College in Mount Pleasant, Iowa.
- January 27 – The Republic of Ezo is proclaimed on the northern Japanese island of Ezo (which will be renamed Hokkaidō on September 20) by remaining adherents to the Tokugawa shogunate.
- February 5 – Prospectors in Moliagul, Victoria, Australia, discover the largest alluvial gold nugget ever found, known as the "Welcome Stranger".
- February 20 – Ranavalona II, the Merina Queen of Madagascar, is baptized.
- February 25 – The Iron and Steel Institute is formed in London.
- February 26 – Mahbub Ali Khan, 2½, begins a 42-year reign as Nizam of Hyderabad.
- March – In Japan, the daimyōs of the Tosa, Hizen, Satsuma and Chōshū Domains are persuaded to return their domains to the Emperor Meiji, leading to creation of a fully centralized government in the country.
- March 1
- March 4 – Ulysses S. Grant is sworn in, as the 18th President of the United States.
- March 9 – Southern Illinois University Carbondale is founded.
- March 18 (O. S. March 6) – Dmitri Mendeleev makes a formal presentation of his periodic table to the Russian Chemical Society.
- March 24 – Titokowaru's War ends with the surrender of the last Māori troops at large, in the South Taranaki District of New Zealand's North Island.
- April 6 – The American Museum of Natural History is founded in New York.
- April 17 – The State of Morelos is created in Mexico.
- May – In France, the opposition, consisting of republicans, monarchists and liberals, polls almost 45% of the vote in national elections.
- May 4–10 – Naval Battle of Hakodate: The Imperial Japanese Navy defeats adherents of the Tokugawa shogunate.
- May 6 – Purdue University is founded in West Lafayette, Indiana.
- May 10 – The First Transcontinental Railroad in North America is completed at Promontory, Utah, by the driving of the "golden spike".
- May 15 – Women's suffrage: In New York, Susan B. Anthony and Elizabeth Cady Stanton form the National Woman Suffrage Association.
- May 18 – One day after surrendering at the land Battle of Hakodate (begun 4 December 1868), Enomoto Takeaki turns over Goryōkaku to Japanese forces, signaling the collapse of the Republic of Ezo.
- May 22 – Sainsbury's first store, in Drury Lane, London, is opened.
- May 24 – John Wesley Powell departs Green River WY, with a company of 9 other men, on a trip down the Green and Colorado Rivers.
- May 26 – Boston University is chartered by the Commonwealth of Massachusetts.
- June 1 – The Cincinnati Red Stockings open the baseball season as the first fully professional team.
- June 2 – Sherwood College is founded in Nainital, India.
- June 15 – John Wesley Hyatt patents celluloid in Albany, New York.
- June 27 – The fortress of Goryōkaku is turned over to Imperial Japanese forces, bringing an end to the Republic of Ezo, the Battle of Hakodate and the Boshin War.
- June 30–July 2 – The first Estonian Song Festival takes place in Tartu.
- October – The 'Edinburgh Seven', led by Sophia Jex-Blake, start to attend lectures at the University of Edinburgh Medical School, the first women in the United Kingdom to do so (although they will not be allowed to take degrees).
- October 2 – India Mohandas Karamchand Gandhi freedom fighter for India was born.
- October 11
- October 16 – England's first residential university-level women's college, the College for Women (predecessor of Girton College, Cambridge), is founded at Hitchin, by Emily Davies and Barbara Bodichon.
- November 4 – The first issue of the scientific journal Nature is published in London, edited by Norman Lockyer.
- November 6 – The first game of American football between two American colleges is played. Rutgers University defeats Princeton University 6–4, in a forerunner to American football and College football.
- November 17 – In Egypt, the Suez Canal, linking the Mediterranean Sea with the Red Sea, is inaugurated in an elaborate ceremony.
- November 19 – The Hudson's Bay Company surrenders its claim to Rupert's Land in Canada, under its letters patent, back to the British Crown.
- November 23 – In Dumbarton, Scotland, the clipper ship Cutty Sark is launched (it is one of the last clippers built, and the only one to survive in the United Kingdom).
- December – Leo Tolstoy's novel War and Peace is published in complete book form, in Russia.
- December 7 – American outlaw Jesse James commits his first confirmed bank robbery, in Gallatin, Missouri.
- December 8 – The First Vatican Council opens in Rome.
- December 10
- December 31 – Paraguayan War: Triple Alliance forces take Asunción.
- The investment bank Goldman Sachs is founded in New York.
- The capital of the Isle of Man moves from Castletown to Douglas.
- Arabella Mansfield became the first woman in the United States awarded a license to practice law, at Mount Pleasant, Iowa.
- James Gordon Bennett, Jr. of the New York Herald asks Henry Morton Stanley to find Dr. David Livingstone.
- The Co-operative Central Board (later Co-operatives UK) is founded in Manchester, England.
- Friedrich Miescher discovers deoxyribonucleic acid (DNA).
- The Ladies National Association for the Repeal of the Contagious Diseases Acts is founded in Great Britain.
- French missionary and naturalist Père Armand David receives the skin of a giant panda from a hunter, the first time this species becomes known to a Westerner; he also first describes a specimen of the "pocket handkerchief tree", which will be named in his honor as Davidia involucrata.
- The University of Otago is founded, making it New Zealand's oldest university.
- Glasgow University Rugby Football Club is founded in Scotland.
- Campbell Soup Company was founded in New Jersey, United States.
- Heinz, as predecessor of Kraft Heinz, a food processing and cheese brand on worldwide, founded in Pennsylvania, United States.
- St. Ignatius College Prep in Chicago is founded, and construction on the school's main building began. It is one of only five buildings that survived the Great Chicago Fire of 1871. The building was designed by the Canadian architect Toussaint Menard in the Second Empire architecture style.