Mass shootings in the United States

Total deaths in US mass shootings from 1982 to 2017, according to Mother Jones.[1]
Locations of US mass shootings in 2015, according to Shooting Tracker.

There is no fixed definition of a mass shooting,[2] but a common definition is an act of violence—excluding gang killings, domestic violence, or terrorist acts sponsored by an organization—in which a gunman kills at least four victims. Using this definition, one study found that nearly one-third of the world's public mass shootings between 1966 and 2012 (90 of 292 incidents) occurred in the United States.[3][4] Using the same definition, Gun Violence Archive records 152 mass shootings in the United States between 1967 and May 2018, averaging eight fatalities per incident when the perpetrator's death is included.[5]

The United States has had more mass shootings than any other country.[6][3][7][8][9] The overwhelming majority of perpetrators are white males who act alone,[10] and they generally either die by suicide afterwards or are restrained or killed by law enforcement officers or civilians.[11]


There is no fixed definition of a mass shooting in the United States.[2] The Investigative Assistance for Violent Crimes Act of 2012, signed into law by Congress in January 2013, defines a "mass killing" as one resulting in at least 3 victims, excluding the perpetrator.[12][2][13][14] In 2015, the Congressional Research Service defined a mass shooting as "a multiple homicide incident in which four or more victims are murdered with firearms, within one event, and in one or more locations in close proximity".[15] A broader definition, as used by the Gun Violence Archive, is that of "4 or more shot or killed, not including the shooter".[16] This definition, of four people shot regardless of whether or not that results in injury or death, is often used by the press and non-profit organizations.[17][18][19][20][21]