September 11 is the 254th day of the year. 111 days remain until the end of the year.
- 600 – Yuknoom Ch’een II, Mayan ruler
- 1862 – O. Henry, American short story writer (d. 1910)
- 1913 – Bear Bryant, American football player and coach (d. 1983)
- 1916 – Ed Sabol, American film producer, co-founded NFL Films (d. 2015)
- 1924 – Tom Landry, American football player and coach (d. 2000)
- 1937 – Queen Paola of Belgium
- 1965 – Paul Heyman, American wrestling promoter, manager, and journalist
- 1977 – Ludacris, American rapper and producer
- 1063 – Béla I of Hungary (b. 1016)
- 1161 – Melisende, Queen of Jerusalem (b. 1105)
- 1680 – Emperor Go-Mizunoo of Japan (b. 1596)
- 1971 – Nikita Khrushchev, Russian general and politician (b. 1894)
- 2001 – 2,977 victims of the September 11 terrorist attacks
- 2002 – Johnny Unitas, American football player and sportscaster (b. 1933)
- 1609 – Henry Hudson discovers Manhattan Island and the indigenous people living there.
- 1789 – Alexander Hamilton is appointed the first United States Secretary of the Treasury.
- 1792 – The Hope Diamond is stolen along with other French crown jewels when six men break into the house where they are stored.
- 1813 – War of 1812: British troops arrive in Mount Vernon and prepare to march to and invade Washington, D.C..
- 1830 – Anti-Masonic Party convention; one of the first American political party conventions.
- 1919 – United States Marine Corps invades Honduras.
- 1941 – Ground breaking commences for The Pentagon, the future home of the United States Department of Defense, sixty years to the day before it was attacked on September 11, 2001.
- 1950 – Korean War: President Harry S. Truman approved military operations north of the 38th parallel.
- 1970 – The Dawson’s Field hijackers release 88 of their hostages. The remaining hostages, mostly Jews and Israeli citizens, are held until September 25.
- 1985 – Pete Rose breaks Ty Cobb’s baseball record for most career hits with his 4,192nd hit.
- 2001 – The September 11 attacks, a series of coordinated suicide attacks killing 2,996 people using four aircraft hijacked by 19 members of al-Qaeda. Two aircraft crash into the World Trade Center in New York City, a third crashes into The Pentagon in Arlington County, Virginia, and a fourth into a field near Shanksville, Pennsylvania.
- 2011 – The National September 11 Memorial & Museum opens on the 10th anniversary of the September 11 attacks.
- 2012 – The U.S. embassy in Benghazi, Libya is attacked, resulting in four deaths.
- 2015 – A crane collapses onto the Masjid al-Haram mosque in Saudi Arabia, killing 111 people and injuring 394 others.
- “I Want to Start My Own Business” Day
- Libraries Remember Day
- National Emergency Responders Day
- Make Your Bed Day
- National Day of Service and Remembrance
- National Hot Cross Bun Day
- Women’s Baseball Day
- National No News Is Good News Day
- Remember Freedom Day
- Patriot Day