The deadliest school shooting in the United States as of September 4, 2024, was the Virginia Tech massacre, with 32 fatalities and 23 injuries. The next deadliest school shooting (based on fatalities) was the Sandy Hook Elementary massacre in Newtown, Connecticut, with 27 fatalities. School shootings in the U.S. Mass shootings in the United States have become a disturbingly common occurrence, and sadly, so have school shootings. The Columbine school shooting is perhaps the most famous in the country’s history, and since 1999 (when the shooting occurred), the number of school shootings has only increased. Many measures have been used to try to prevent school shootings, including security guards and metal detectors being deployed in schools, and even the suggestion that teachers be allowed to carry guns in schools. Gun control Gun control in the United States is a sticky issue, since gun ownership is enshrined in the Constitution. Some advocate for stricter gun control laws to try to prevent future mass shootings, while others say that this is unconstitutional. Gun ownership rates in the U.S. are high, with the share of American households owning at least one firearm remaining relatively steady since 1972.

THIS DATASET WAS LAST UPDATED AT 8:11 PM EASTERN ON JULY 30

OVERVIEW

2019 had the most mass killings since at least the 1970s, according to the Associated Press/USA TODAY/Northeastern University Mass Killings Database.

In all, there were 45 mass killings, defined as when four or more people are killed excluding the perpetrator. Of those, 33 were mass shootings . This summer was especially violent, with three high-profile public mass shootings occurring in the span of just four weeks, leaving 38 killed and 66 injured.

A total of 229 people died in mass killings in 2019.

The AP's analysis found that more than 50% of the incidents were family annihilations, which is similar to prior years. Although they are far less common, the 9 public mass shootings during the year were the most deadly type of mass murder, resulting in 73 people's deaths, not including the assailants.

One-third of the offenders died at the scene of the killing or soon after, half from suicides.

About this Dataset

The Associated Press/USA TODAY/Northeastern University Mass Killings database tracks all U.S. homicides since 2006 involving four or more people killed (not including the offender) over a short period of time (24 hours) regardless of weapon, location, victim-offender relationship or motive. The database includes information on these and other characteristics concerning the incidents, offenders, and victims.

The AP/USA TODAY/Northeastern database represents the most complete tracking of mass murders by the above definition currently available. Other efforts, such as the Gun Violence Archive or Everytown for Gun Safety may include events that do not meet our criteria, but a review of these sites and others indicates that this database contains every event that matches the definition, including some not tracked by other organizations.

This data will be updated periodically and can be used as an ongoing resource to help cover these events.

Using this Dataset

To get basic counts of incidents of mass killings and mass shootings by year nationwide, use these queries:

Mass killings by year

Mass shootings by year

To get these counts just for your state:

Filter killings by state

Definition of "mass murder"

Mass murder is defined as the intentional killing of four or more victims by any means within a 24-hour period, excluding the deaths of unborn children and the offender(s). The standard of four or more dead was initially set by the FBI.

This definition does not exclude cases based on method (e.g., shootings only), type or motivation (e.g., public only), victim-offender relationship (e.g., strangers only), or number of locations (e.g., one). The time frame of 24 hours was chosen to eliminate conflation with spree killers, who kill multiple victims in quick succession in different locations or incidents, and to satisfy the traditional requirement of occurring in a “single incident.”

Offenders who commit mass murder during a spree (before or after committing additional homicides) are included in the database, and all victims within seven days of the mass murder are included in the victim count. Negligent homicides related to driving under the influence or accidental fires are excluded due to the lack of offender intent. Only incidents occurring within the 50 states and Washington D.C. are considered.

Methodology

Project researchers first identified potential incidents using the Federal Bureau of Investigation’s Supplementary Homicide Reports (SHR). Homicide incidents in the SHR were flagged as potential mass murder cases if four or more victims were reported on the same record, and the type of death was murder or non-negligent manslaughter.

Cases were subsequently verified utilizing media accounts, court documents, academic journal articles, books, and local law enforcement records obtained through Freedom of Information Act (FOIA) requests. Each data point was corroborated by multiple sources, which were compiled into a single document to assess the quality of information.

In case(s) of contradiction among sources, official law enforcement or court records were used, when available, followed by the most recent media or academic source.

Case information was subsequently compared with every other known mass murder database to ensure reliability and validity. Incidents listed in the SHR that could not be independently verified were excluded from the database.

Project researchers also conducted extensive searches for incidents not reported in the SHR during the time period, utilizing internet search engines, Lexis-Nexis, and Newspapers.com. Search terms include: [number] dead, [number] killed, [number] slain, [number] murdered, [number] homicide, mass murder, mass shooting, massacre, rampage, family killing, familicide, and arson murder. Offender, victim, and location names were also directly searched when available.

This project started at USA TODAY in 2012.

Contacts

Contact AP Data Editor Justin Myers with questions, suggestions or comments about this dataset at jmyers@ap.org. The Northeastern University researcher working with AP and USA TODAY is Professor James Alan Fox, who can be reached at j.fox@northeastern.edu or 617-416-4400.

On October 1, 2017, the highest number of fatalities from a mass shooting in the United States was recorded when Stephen Paddock attacked a crowd of concert-goers on the Las Vegas strip, killing 58 and injuring 546 others, then taking his own life before authorities could apprehend him. Most recently, one of the worst mass shootings in the U.S. occurred in Maine on October 26, 2023, when Robert Card, an Army reservist and firearms instructor, opened fire in a bowling alley and a bar, killing 18 and injuring 13 others. Card then became the focus of a two-day-long manhunt, until he was found dead from a self-inflicted gunshot.

As of July 14, 2025, there have been a total of 277 school shootings in California since 1966, the most out of any state. Texas had the second highest number of school shootings within this time period, with 237 shootings. The source defines a school shooting as every time a gun is brandished, fired, or a bullet hits school property for any reason, regardless of the number of victims (including zero), time, day or the week, or reason, including gang shootings, domestic violence, shootings at sports games and after hours school events, suicides, fights that escalate into shootings, and accidents.

From 2008 to April 25, 2025, the District of Columbia had the highest rate of school shootings nationwide, totaling around **** school shootings per 100,000 residents. Louisiana, Delaware, Maryland, and Alabama rounded out the top five states with the highest school shooting rates relative to their populations. In contrast, there were no school shootings recorded in Montana, Wyoming, New Hampshire, Vermont, and Rhode Island within the provided time period. In addition to K-12 schools and college campuses, gun-related violence in the United States often occurs at workplaces, places of worship, and restaurants and bars. The source defines school shootings as incidents of gun violence which occurred on school property, from kindergartens through colleges/universities, and at least one person was shot, not including the shooter. School property includes, but is not limited to, buildings, fields, parking lots, stadiums and buses. Accidental discharges of firearms are included, as long as at least one person is shot, but not if the sole shooter is law enforcement or school security.

As of September 2024, California had the most mass shootings in the United States, with 26 total shootings since 1982. The source defines a mass shooting as a shooting where three or more people were killed. Recently, a mass shooting occurred in the state of Maine on October 26, 2023, during which one of the highest number of fatalities from a mass shooting was recorded after Robert Card opened fire in a bowling alley and a bar, killing 18 and injuring 13 others. Firearms in the U.S. Mass shootings in the United States are disturbingly common. In comparison with other Western countries, there are significantly more shootings in the U.S., which some theorize is due to the relatively lax gun control laws. Gun control laws in the U.S. are dependent on the state, and the right to own a firearm is enshrined in the United States Constitution. Mass shootings The worst mass shooting in the U.S. was the Las Vegas Strip massacre in 2017, which resulted in 58 deaths and 546 injuries. 13 of the worst mass shootings in the United States have occurred since 2015 and the vast majority of these incidents in the U.S. have been carried out by shooters who are White and male.

Between 1966 and May 19, 2025, 872 victims were wounded while 260 victims were killed during K-12 school shootings resulting from an escalation of dispute, defined as a situation in which there was a physical or verbal altercation between the shooter and the victim(s) before the shooting or where shots were fired in retaliation for a previous attack, in the United States. Indiscriminate shootings, where the shooter intends to kill as many people as possible with no particular target, have also been highlighted as a significant source of harm in K-12 schools, with approximately 572 victims either wounded or killed within the provided time period. In comparison, school shootings attributed to anger over getting bad grades or facing disciplinary measures typically lead to a scenario in which teachers or school administrators are the primary targets of school shooters. Totaling less than 100 victims, this type of situation also encompasses shootings carried out by school employees against coworkers or superiors after poor performance evaluations, suspensions, or job losses.

ABSTRACT Communication is a dynamic and open process and, in the field of health, it involves from the transmission of messages to obtaining information. “Bad news” can be considered all information that involves a drastic and negative change in the patient’s life and regarding the perspective of the future. To give “bad news” to the patient includes everything from a diagnosis of a terminal illness, to pathologies that interfere with their quality of life. In Brazil, there is a problem regarding this subject, because there is not much content in the curricular grid about the communication of bad news, as well as little practice on the use of communication methods. This directly impacts both the professional and personal life of the future physician, as well as the relationship with the patient. The present article is a cross-sectional descriptive study, carried out in the cities of Joinville and Jaraguá do Sul, and the project was submitted to and approved by the institutions’ ethical assessment according to Brazilian standards. It aims to describe the understanding of sixth-year undergraduate medical students and first-year residents when dealing with the reporting of bad news. The sample consisted of 63 participants, with data collected from a questionnaire, between April and September 2018 and analyzed descriptively in terms of frequency of each response. As for the results, it is noteworthy that the task considered the most difficult one was to talk about the end of an attempted curative treatment; 61% considered themselves reasonably skilled regarding the ability to communicate bad news, and that involving the family member or patient in the decision-making process is the most difficult factor during the discussion. In addition, 74% of the participants were unaware of any method of communication and 44% believed that practical classes with real patients would be an effective way of learning. Therefore, it is concluded that the lack of preparation to mediate such situations implies in heterogeneous behaviors that could be avoided with instructions and would contribute to the best training during undergraduate medical school.

Abstract “Bad news”, defined as information with huge emotional valence and potential to change personal perspectives, is, by definition, a challenge for physicians. However, the subject is not always taught in medical schools. This systematic literature review compiles all articles regarding communication of bad news after researching in databases for “medical school” and “bad news” in English, Portuguese and Spanish. The criterion was to include articles that elucidated about teaching techniques. From all 313 papers, we included 27 and classified their strategies. Most results showed that mixed strategies are more common and that, in general, the subject is well-received and appreciated by students, who reported an improvement in communicative capability after the training. We conclude that all techniques are valid and medical schools should focus on integrating this training in their regular curriculum.

Handguns are the most common weapon type used in mass shootings in the United States, with a total of 167 different handguns being used in 117 incidents between 1982 and September 2024. These figures are calculated from a total of 151 reported cases over this period, meaning handguns are involved in about 78 percent of mass shootings. The involvement of semi-automatic rifles in mass shootings Owing to their use in several high-profile mass shootings, there has been much public discussion over the suitability or necessity of assault weapons for the purpose of self-defense. While any definition of assault weapon is contentious, semi-automatic rifles are generally the main focus of debates around this issue. Since 1982, there has been a known total 65 mass shootings involving rifles, mostly semi-automatics. This figure is underreported, however, as it excludes the multiple semi-automatic (and fully automatic) rifles used in the 2017 Las Vegas Strip massacre – the worst mass shooting in U.S. history, killing 58 and wounding 546. In fact, semi-automatic rifles were featured in four of the five deadliest mass shootings, being used in the Orlando nightclub massacre, Sandy Hook Elementary massacre and Texas First Baptist Church massacre. Mass shootings and gun control Despite evidence of strict gun control measures reducing the frequency and severity of mass shootings in countries like Australia, citizens in the United States remain deeply divided over the issue. According to a survey about the expected impact of gun laws on the number of mass shootings, a slim majority of Americans believe that gun control measures will have little-to-no effect. Most likely, this opinion is influenced by an underlying commitment among many in the U.S. to the greater importance of protecting gun ownership rights than limiting access to firearms. This sits in sharp contrast to many other developed countries. For example, most Canadians support a ban on civilian owned firearms.

The statistic shows the number of victims of the worst mass shootings in western democratic countries from 1966 to 2012. On December 14, 2012, a gunman killed 26 people - 20 of them children aged 5 to 10 - in a shooting at an elementary school in Newtown, Connecticut. He committed suicide afterwards. Gun policy in the USA Over the last few years, mass shootings and accidents with children at shooting ranges have shaped national debates about the gun laws in the United States.

According to the Gallup survey across the United States in January 2014, 40 percent of the U.S. population stated they are totally satisfied with the existing gun laws in the United States, while 31 percent of the respondents stated they are dissatisfied, they want stricter laws.

The survey among American adults, which was conducted by the Pew Research Center in 2012 shortly after the Aurora movie theater shooting, on what they consider more important – the right to bear arms or controlling gun ownership, shows that 47 percent of the participants said the control of gun ownership is more important than the protection of the right to own guns.

The attitude towards gun control varies from generation to generation, 55 percent of the Millennials stated that controlling gun ownership is more important than protecting the gun rights, while 44 percent of the Silent generation stated the same.

The number of homicides by firearms has decreased over the last few years, 11,040 homicides by firearm were counted in 2003, while 9,960 homicides by firearm were counted in 2010. Homicide takes several forms, for example murder but homicide is not always a crime, it also includes affirmative defense, insanity, self-defense or the execution of convicted criminals.

America’s gun policy makes it possible for the American population to have a gun in their home on their own property, all U.S. states have imposed their own firearm restrictions. The percentage of Americans who have a gun in their home shifted from 40 percent in 1996 to 47 percent in 2011.

The second-deadliest workplace shooting in the United States took place in Edmond, Oklahoma in 1986 at a United States post office. There were 15 fatalities and six injuries in this shooting, and the incident inspired the American phrase “going postal.”

Workplace shootings

A mass shooting in the United States is generally defined as an incident where four or more people were injured or killed, though this can vary by source. It is sometimes difficult to identify the cause of workplace killings (also called rampage killings), although many involved disgruntled workers and some involve perpetrators with mental health problems.

Mass shootings in the United States

The vast majority of mass shootings in the United States are perpetrated by male assailants, and only four shootings have been carried out by women since 1982. Additionally, most of the weapons used in mass shootings were acquired through legal means, with only 16 incidents involving illegally obtained weapons since 1982.