| 66961 | June 11 | Holiday and observance | Student Day (Honduras) |
| 66962 | June 12 | Event | 1381 – Peasants' Revolt: In England, rebels arrive at Blackheath. |
| 66963 | June 12 | Event | 1418 – An insurrection delivers Paris to the Burgundians. |
| 66964 | June 12 | Event | 1429 – Hundred Years' War: Joan of Arc leads the French army in their capture of the city and the English commander, William de la Pole, 1st Duke of Suffolk in the second day of the Battle of Jargeau. |
| 66965 | June 12 | Event | 1550 – The city of Helsinki, Finland (belonging to Sweden at the time) is founded by King Gustav I of Sweden. |
| 66966 | June 12 | Event | 1560 – Battle of Okehazama: Oda Nobunaga defeats Imagawa Yoshimoto. |
| 66967 | June 12 | Event | 1653 – First Anglo-Dutch War: The Battle of the Gabbard begins and lasts until June 13. |
| 66968 | June 12 | Event | 1665 – England installs a municipal government in New York City (the former Dutch settlement of New Amsterdam). |
| 66969 | June 12 | Event | 1758 – French and Indian War: Siege of Louisbourg: James Wolfe's attack at Louisbourg, Nova Scotia commences. |
| 66970 | June 12 | Event | 1775 – American Revolution: British general Thomas Gage declares martial law in Massachusetts. The British offer a pardon to all colonists who lay down their arms. There would be only two exceptions to the amnesty: Samuel Adams and John Hancock, if captur |
| 66971 | June 12 | Event | 1776 – The Virginia Declaration of Rights is adopted. |
| 66972 | June 12 | Event | 1798 – Irish Rebellion of 1798: Battle of Ballynahinch. |
| 66973 | June 12 | Event | 1860 – The State Bank of the Russian Empire is established. |
| 66974 | June 12 | Event | 1864 – American Civil War, Overland Campaign: Battle of Cold Harbor: Ulysses S. Grant gives the Confederate forces under Robert E. Lee a victory when he pulls his Union troops from their positions at Cold Harbor, Virginia and moves south. |
| 66975 | June 12 | Event | 1889 – Eighty are killed in the Armagh rail disaster near Armagh in what is now Northern Ireland. |
| 66976 | June 12 | Event | 1898 – Philippine Declaration of Independence: General Emilio Aguinaldo declares the Philippines' independence from Spain. |
| 66977 | June 12 | Event | 1899 – New Richmond tornado: The eighth deadliest tornado in U.S. history kills 117 people and injures around 200. |
| 66978 | June 12 | Event | 1905 – The Servants of India Society was established in Pune, India by Gopal Krishna Gokhale. |
| 66979 | June 12 | Event | 1922 – At Windsor Castle, King George V receives the colours of the six Irish regiments that are to be disbanded: The Royal Irish Regiment, the Connaught Rangers, the South Irish Horse, the Prince of Wales's Leinster Regiment, the Royal Munster Fusiliers |
| 66980 | June 12 | Event | 1935 – A ceasefire is negotiated between Bolivia and Paraguay, ending the Chaco War |
| 66981 | June 12 | Event | 1939 – Shooting begins on Paramount Pictures' Dr. Cyclops, the first horror film photographed in three-strip Technicolor. |
| 66982 | June 12 | Event | 1939 – The Baseball Hall of Fame opens in Cooperstown, New York. |
| 66983 | June 12 | Event | 1940 – World War II: Thirteen thousand British and French troops surrender to Major General Erwin Rommel at Saint-Valery-en-Caux. |
| 66984 | June 12 | Event | 1942 – Anne Frank receives a diary for her thirteenth birthday. |
| 66985 | June 12 | Event | 1943 – Holocaust: Germany liquidates the Jewish Ghetto in Brzeżany, Poland (now Berezhany, Ukraine). Around 1,180 Jews are led to the city's old Jewish graveyard and shot. |
| 66986 | June 12 | Event | 1944 – American paratroopers of the 101st Airborne Division secure the town of Carentan. |
| 66987 | June 12 | Event | 1954 – Pope Pius XII canonises Dominic Savio, who was 14 years old at the time of his death, as a saint, making him the youngest unmartyred saint in the Roman Catholic Church. |
| 66988 | June 12 | Event | 1963 – Civil rights leader Medgar Evers is murdered in front of his home in Jackson, Mississippi by Ku Klux Klan member Byron De La Beckwith. |
| 66989 | June 12 | Event | 1964 – Anti-apartheid activist and ANC leader Nelson Mandela is sentenced to life in prison for sabotage in South Africa. |
| 66990 | June 12 | Event | 1967 – The United States Supreme Court in Loving v. Virginia declares all U.S. state laws which prohibit interracial marriage to be unconstitutional. |