May 6 - Johan Ludvig Runeberg, Finnish poet (b. 1804)
June 3 - Ludwig Ritter von Köchel, Austrian musicologist (b. 1800)
September 5 - Crazy Horse, Lakota (Sioux) chief (b. 1849)
October 28 - Robert Swinhoe, British naturalist (b. 1835)
December 28 - Nikolai Alekseevich Nekrasov, Russian poet (b. 1821)
January 1 - Queen Victoria of Britain is proclaimed Empress of India.
January 8 - Crazy Horse and his warriors fight their last battle with the United States Cavalry at Wolf Mountain (Montana Territory).
January 22 - Arthur Tooth, an Anglican clergyman is taken into custody after being prosecuted for using ritualist practices.
March 2 - U.S. presidential election, 1876: Just two days before inauguration, the U.S. Congress declares Rutherford B. Hayes the winner of the election even though Samuel J. Tilden had won the popular vote on November 7, 1876.
March 3 - Rutherford B. Hayes is privately inaugurated as the 19th President of the United States (his public inauguration coming on March 5).
March 4 - Pyotr Ilyich Tchaikovsky's ballet Swan Lake premiers at the Bolshoi Theatre in Moscow.
March 15 - The first Test cricket match begins between England and Australia.
March 31 - The family with samurai antecedents who responded to the Saigo army in Ōita Nakatsu rebels.
April 12 - The United Kingdom annexes the Transvaal.
April 24 - Russo-Turkish War, 1877–1878: Russia declares war on Ottoman Empire.
May 5 - Indian Wars: Sitting Bull leads his band of Lakota into Canada to avoid harassment by the United States Army under Colonel Nelson Miles.
May 6 - Chief Crazy Horse of the Oglala Sioux surrenders to United States troops in Nebraska.
May 9 - Mihail Kogălniceanu reads, in the Chamber of Deputies, the Declaration of Independence of Romania. This day became the Independence Day of Romania.
May 10 - Romania declares itself independent from Turkey, following the Senate adoption of Mihail Kogălniceanu's Declaration of Independence. This act is recognized on March 26, 1881 after the end of the Romanian War of Independence.
June 15 - Henry Ossian Flipper becomes the first African American cadet to graduate from the United States Military Academy.
June 17 - Indian Wars: Battle of White Bird Canyon
June 20 - Alexander Graham Bell installs the world's first commercial telephone service in Hamilton, Ontario, Canada.
June 21 - The Molly Maguires, ten Irish immigrants, are hanged at the Schuylkill County and Carbon County, Pennsylvania prisons.
July 10 - The then-villa of Mayagüez, Puerto Rico, formally receives its city charter from the Royal Crown of Spain.
July 20 - Rioting in Baltimore, Maryland by Baltimore and Ohio Railroad workers is put down by the state militia, resulting in nine deaths.
July 21 - After rioting by Baltimore and Ohio Railroad workers and the deaths of nine rail workers at the hands of the Maryland militia, workers in Pittsburgh, Pennsylvania stage a sympathy strike that is met with an assault by the state militia.