|Holiday name||Holiday location||Holiday type|
|King's Mother's Birthday||Cambodia||Observance|
|Constitution Day||Seychelles||Public Holiday|
|International Picnic Day||-||Unofficial (Activity & Action, Food & Drinks)|
|International Panic Day||-||Unofficial (Awareness & Cause, Health & Body)|
|National Go Fishing Day||-||Unofficial (Activity & Action, Nature & Environment)|
|National Splurge Day||-||Unofficial (Fun & Joy, Lifestyle)|
|World Juggling Day||-||Unofficial (Fun & Joy, Hobby & Creativity)|
Historical Events on June 18
- 1778: During the American Revolutionary War, the city of Philadelphia in Pennsylvania is abandoned by British forces.
- 1799: Lord Keith and his British fleet captures a frigate squadron led by Rear Admiral Perree during the Action June 18th, 1799.
- 1812:S President James Madison signs the declaration of war against the United Kingdom during the War of 1812.
- 1815: Napoleon Bonaparte is defeated at the Battle of Waterloo by the Duke of Wellington. This forces him to abdicate the throne of France for the second time.
- 1830: Algeria is invaded by France.
- 1858: Charles Darwin receives notes from Alfred Russel Wallace that come to the same exact conclusions as Darwin’s Theory of Evolution. This prompts Darwin to go ahead and publish his theory.
- 1873: When she tries to vote in the 1872 U.S. Presidential election, Susan B. Anthony is fine a hundred dollars.
- 1908: The University of the Philippines is founded on this date.
- 1923: American taxi company Checker Taxi puts its first taxi out on the streets.
- 1940: British Prime Minister Winston Churchill delivers his “Finest Hour” speech on this date.
- 1945: William Brooke Joyce, also known as Lord Haw Haw, is charged with High Treason for his pro-German propaganda broadcasting during World War II.
- 1953: A U.S Air Force C-124 crashes near Tachikawa, Japan. Over 128 people were killed.
- 1965: National Liberation Front guerrilla fighters in South Vietnam are bombed by U.S B-52 bombers during the Vietnam War.
- 1979: Salt II (the Strategic Arms Limitation Talks II) is signed between the U.S and the U.S.S.R.
Famous Birthdays on June 18
- French physician and Nobel Prize laureate, Charles Louis Alphonse Laveran is born in 1845.
- American publisher E.W. Scripps is born in 1854.
- American businessman and philanthropist, Henry Clay Folger is born in 1857.
- American actress Blanche Sweet is born in 1896.
- American journalist, screenwriter and critic, Roger Ebert is born in 1942.
- English singer-songwriter and guitarist, Paul McCartney is born in 1942.
- Canadian actress Linda Thorson is born in 1947.