Historic Event
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
Historic Event
May 10 US President Rutherford B. Hayes has 1st White House telephone installed, in the telegraph room
- May 12 Ottawa Rough Riders 1st outside competition vs Britannia
- May 13 Caesar Franck's symphonic poem "Lesson Eolides" premieres
- May 16 May 16, 1877 political crisis in France.
- May 17 Edwin T Holmes installs 1st telephone switchboard burglar alarm
- May 22 3rd Kentucky Derby: Billy Walker aboard Baden-Baden wins in 2:38
- May 24 5th Preakness: C Holloway aboard Cloverbrook wins in 2:45.5