1867 1868 1869 - 1870 - 1871 1872 1873
1840s 1850s 1860s - 1870s - 1880s 1890s 1900s
Events of 1870
- January 1
- January 3 – Construction of the Brooklyn Bridge begins.
- January 6 – The Musikverein, Vienna is inaugurated in Austria-Hungary.
- January 10 – John D. Rockefeller incorporates Standard Oil.
- January 15 – A political cartoon for the first time symbolizes the United States Democratic Party with a donkey ("A Live Jackass Kicking a Dead Lion" by Thomas Nast for Harper's Weekly).
- January 26 – Reconstruction: Virginia rejoins the Union.
- January 27 – The first college sorority, Kappa Alpha Theta, is established at DePauw University.
- February – Vrain Denis-Lucas is sentenced to 2 years in prison for multiple forgery in Paris.
- February 1 – Goodna State School in Goodna, Queensland, Australia is founded.
- February 2 – It is revealed that the famed Cardiff Giant is just carved gypsum and not the petrified remains of a human.
- February 3 – The 15th Amendment to the United States Constitution, guaranteeing African-Americans the right to vote, is passed.
- February 9 – Army Weather Bureau (within Army Signal Corps) created.
- February 10
- February 12 – Women gain the right to vote in Utah Territory.
- February 23 – Military control of Mississippi ends and it is readmitted to the Union.
- February 25 – Hiram Rhodes Revels, a Republican from Mississippi, is sworn into the United States Senate, becoming the first African American ever to sit in the U.S. Congress.
- February 26 – In New York City, the first pneumatic subway is opened.
- February 28 – The Bulgarian Exarchate is established by decree of Sultan Abd-ul-Aziz of the Ottoman Empire.
- March 1 – Marshal Francisco Solano López' last troops are cornered by Triple Alliance troops at Cerro Cora. López refuses to surrender and is killed. Fighting ends in Paraguay – the War of the Triple Alliance is over.
- March 4 – Thomas Scott is executed by Louis Riel's provisional government during the Red River Rebellion in modern day Manitoba Canada.
- March 5 – First ever international Association Football match between England and Scotland at the Oval, London. Organised by the Football Association.
- March 19 – The Ohio Legislature passes the Cannon Act, thereby establishing the Ohio Agriculture and Mechanical College, later Ohio State University.
- March 24 – Syracuse University is established and officially opens.
- March 30
- April: The Chicago Base Ball Club, later to be known as the Chicago White Stockings, and ultimately the Chicago Cubs, play their first game against the St. Louis Unions of the National Association of Base Ball Players, an amateur league.
- May 12 – The Canadian province of Manitoba is created in response to Louis Riel's Red River Rebellion.
- May 14 – The first rugby match is played in New Zealand, between the Nelson Football Club and Nelson College.
- May 24 – The Port Adelaide Football Club plays their first match of Australian rules football at Buck's Flat, Glanville, South Australia.
- June 22 – Office of the Solicitor General set up to supervise and conduct government litigation in the United States Supreme Court.
- June 22 – The U.S. Congress creates the United States Department of Justice.
- June 26
- July 13 – The Ems Dispatch serves as a reason for a war between Prussia and France.
- July 15 – Reconstruction: Georgia becomes the last former Confederate state to be readmitted to the Union, and the C.S.A. is dissolved.
- July 18 – Pastor Aeternus: Pope Pius IX declares papal infallibility in matters of faith and morals.
- July 19 – Franco-Prussian War: France declares war on Prussia. The King of Prussia Wilhelm revives the Iron Cross.
- August 8 – The Republic of Ploieşti, an uprising against Domnitor Carol of Romania, fails.
- August 24 – The Red River Rebellion ends with the arrival of the Wolseley Expedition and the fleeing of Louis Riel.
- September 2 – Franco-Prussian War – Battle of Sedan: Prussian forces defeat the French armies and take emperor Napoleon III and 100,000 of his soldiers prisoner at Sedan.
- September 4 – Emperor Napoleon III of France is deposed and the Third Republic is declared. Empress Eugenie flees to England with her children.
- September 6 – Louisa Ann Swain of Laramie, Wyoming, becomes the first woman in the United States to cast a vote legally since 1807.
- September 18 – Old Faithful Geyser is observed and named by Henry D. Washburn during the Washburn-Langford-Doane Expedition to Yellowstone.
- September 20 – With Bersaglieri soldiers entering Rome at Porta Pia, the unification of Italy is completed, ending the last remnant of the Papal States.
- October 2 – A plebiscite held in Rome supports, by 133,681 votes to 1,507, the annexation of the city by Italy.
- October 6 – Rome becomes the capital of unified Italy.
- October 8 – Leon Michel Gambetta escapes the besieged Paris in a hot-air balloon.
- November 1 – In the United States, the newly created Weather Bureau (later renamed the National Weather Service) makes its first official meteorological forecast: "High winds at Chicago and Milwaukee... and along the Lakes".
- November 16 – The Spanish Cortes Generales proclaims Amadeo de Saboya as King Amadeus I of Spain.
- December 30 – Juan Prim, prime minister of Spain, is assassinated.