Timeline of terrorist attacks in the United States

Notable terrorist attacks in the U.S.

United Airlines Flight 175 crashes into the south tower of the World Trade Center in New York City during the September 11 attacks

An aerial view, looking from the north, of the destruction of the Alfred P. Murrah Federal Building after the Oklahoma City Bombing

A team of men and a lone figure in an orange vest are assembled near to a cordoned-off area of rubble produced by the 1993 World Trade Center bombing

Spectators provide aid to victims following the initial pressure-cooker bomb detonation during the 2013 Boston Marathon bombing, an attack that killed three people and injured over 260 others

The Timeline of terrorism in the United States is a chronological list of terrorist attacks and plots that have occurred in the United States. Terrorism is defined by the Federal Bureau of Investigation as the unlawful use of force or violence against persons or property to intimidate or coerce a government, civilian population, or any segment thereof in furtherance of political or social objectives.^[1] This timeline includes incidents committed by both domestic and international actors, covering a wide range of ideologies and motivations.

The deadliest terrorist attack in United States history was the September 11 attacks, in which 2,977 victims were killed when al-Qaeda operatives hijacked four commercial airliners in 2001. Other large-scale attacks include the 1995 Oklahoma City bombing, which killed 168 people; the 1857 Mountain Meadows Massacre, in which 120 - 140 people were killed; and the 2016 Pulse nightclub shooting, which resulted in 50 deaths. These remain the 4 most severe acts of terrorism in the country.^[2]

Patterns of terrorism in the United States have shifted significantly over time. Early incidents included anarchist bombings and politically motivated assassinations in the late 19th and early 20th centuries, as well as violence linked to racial conflict, civil rights struggles, Puerto Rican nationalist movements, and opposition to the Vietnam War. Since the late 20th century, major themes include anti-government extremism, jihadist-inspired attacks, and white nationalism.

Between 2010 and 2021, at least 231 terrorist incidents or plots were documented in the United States, resulting in approximately 145 deaths and more than 370 injuries.^[3] In 2021 alone, there were 73 recorded plots or attacks, compared with 29 in 2015.^[4]