Wikipedia:Selected anniversaries/June 18
- 1812 - The United States declared war against Great Britain, beginning the War of 1812.
- 1815 - Napoléon Bonaparte fought and lost his final battle, the Battle of Waterloo.
- 1858 - Charles Darwin received a manuscript by Alfred Russel Wallace on evolution, which prompted him to publish his theory.
- 1873 - Woman suffrage activist Susan B. Anthony was fined $100 for attempting to vote in the 1872 U.S. presidential election.
- 1979 - The SALT II treaty was signed by the United States and the Union of Soviet Socialist Republics.