In what year did the 9/11 attacks occur?

The 9/11 attacks occurred in 2001. On September 11, 2001, 19 al-Qaeda terrorists hijacked four commercial airplanes in a coordinated attack against the United States. Two planes struck the World Trade Center towers in New York City, one hit the Pentagon in Arlington County, Virginia, and the fourth crashed in Pennsylvania after passengers resisted the hijackers.

The attacks killed 2,977 victims, not counting the 19 hijackers, and caused the collapse of both World Trade Center towers. The event is commonly called “9/11,” pronounced “nine eleven,” after the American date format for September 11.

A common mix-up is confusing the year with later events that followed it. The U.S. invasion of Afghanistan began in October 2001, while the Iraq War began in 2003. Those conflicts were consequences of the wider post-9/11 period, not the year of the attacks themselves.