Casualties of the September 11 attacks

The September 11 attacks were the deadliest terrorist attacks in human history, causing the deaths of 2,996 people, including 19 hijackers who committed murder–suicide and 2,977 victims. Thousands more were injured, and long-term health effects have arisen as a consequence of the attacks. New York City took the brunt of the death toll when the Twin Towers of the World Trade Center complex in Lower Manhattan were attacked, with an estimated 1,700 victims from the North Tower and around a thousand from the South Tower. Two hundred miles southwest in Arlington County, Virginia, another 125 were killed in the Pentagon. The remaining 265 fatalities included the ninety-two passengers and crew of American Airlines Flight 11, the sixty-five aboard United Airlines Flight 175, the sixty-four aboard American Airlines Flight 77 and the forty-four aboard United Airlines Flight 93. The attack on the World Trade Center's North Tower alone made the September 11 attacks the deadliest act of terrorism in human history.

Most of those who perished were civilians, except for: 343 members of the New York City Fire Department and New York Fire Patrol; 71 law enforcement officers who died in the World Trade Center and on the ground in New York City; 55 military personnel who died at the Pentagon in Arlington County, Virginia; a U.S. Fish and Wildlife Service officer who died when Flight 93 crashed into a field near Shanksville, Pennsylvania; and the 19 terrorists who died on board the four aircraft. At least 102 countries lost citizens in the attacks.

Initially, a total of 2,603 victims were confirmed to have been killed at the World Trade Center site. In 2007, the New York City medical examiner's office began to add people who died of illnesses caused by exposure to dust from the site to the official death toll.