- September 16- The Mexican War of Independence begins.
- August 24 - Agustin Iturbide crushes the insurgents led by Vicente Guerrero.
- Unknown - In response to atrocities committed by Spain on the Mexican people, the United States declares war against Spain.
- July 27 - The Treaty of Guadalupe is signed. Spain recognizes the independence of Mexico and cedes its colonies in the Caribbean to the United States
- December 7 - After months of tension, revolution breaks out across Acadia, Upper and Lower Canada. The three colonies unite to form the Republic of Laurentia in Navy Island.
- January 5 - The United Kingdom recognizes the independence of Laurentia.
- April - The Republic of Laurentia is peacefully dissolved. Acadia and Upper Canada move to join the United States, and Lower Canada establishes the Republic of Quebec.
- August - Acadia and Upper Canada are annexed by the United States.
- January 24 - Gold is discovered in Mexico (Nevada and Alta California) and the United States (Oregon Territory), a population boom occurs in this region.
- Unknown - President Johnson is impeached by the House and Senate in 1867. Because he did not have a Vice President, Benjamin F. Wade becomes President.
- Unknown - The United Kingdom purchases Alaska from the Russian Empire.
- June 30 - The U.S. Senate approves the Annexation of Haiti.
- November 13 - The United States annexes Panama.
- July 16 - A nuclear bomb is tested in the Jornada del Muerto Desert in southern New Mexico by the United States and Mexico.
- April 4 - Mexico signs the North Atlantic Treaty, becoming a member of NATO.