Mass shootings are incidents involving multiple victims of firearm related violence. Definitions vary, with no single, broadly accepted definition. One definition is an act of public firearm violence—excluding gang killings, domestic violence, or terrorist acts sponsored by an organization—in which a shooter kills at least four victims. Using this definition, a 2016 study found that nearly one-third of the world's public mass shootings between 1966 and 2012 occurred in the United States, In 2017 The New York Times recorded the same total of mass shootings for that span of years. A 2023 report published in JAMA covering 2014 to 2022, found there had been 4,011 mass shootings in the US, most frequent around the southeastern U.S. and Illinois. This was true for mass shootings that were crime-violence, social-violence, and domestic violence-related. The highest rate was found in the District of Columbia, followed by Louisiana and Illinois.

Gun violence is a term of political, economic and sociological interest referring to the tens of thousands of annual firearms-related deaths and injuries occurring in the United States. In 2022, up to 100 daily fatalities and hundreds of daily injuries were attributable to gun violence in the United States. In 2018, the most recent year for which data are available, the Centers for Disease Control and Prevention's (CDC) National Center for Health Statistics reported 38,390 deaths by firearm, of which 24,432 were suicides. The national rate of firearm deaths rose from 10.3 people for every 100,000 in 1999 to 11.9 people per 100,000 in 2018, equating to over 109 daily deaths. In 2010, there were 19,392 firearm-related suicides, and 11,078 firearm-related homicides in the U.S. In 2010, 358 murders were reported involving a rifle while 6,009 were reported involving a handgun; another 1,939 were reported with an unspecified type of firearm. In 2011, a total of 478,400 fatal and nonfatal violent crimes were committed with a firearm.