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.

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.

Between 1966 and April 28, 2025, K-12 school shootings which took place during morning classes recorded the greatest number of victims in the United States, with 404 victims wounded and 176 victims killed. Within that same time period, 332 victims were wounded, while 106 victims were killed, in K-12 school shootings occurring at the time of afternoon classes.

THIS DATASET WAS LAST UPDATED AT 2:11 AM EASTERN ON JUNE 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.

Between 1966 and June 19, 2025, K-12 school shootings which took place in parking lots recorded the greatest number of victims in the United States, with 444 victims wounded and 196 victims killed within the provided time period. Shootings occurring in hallways, at the front of school, beside buildings, and in classrooms rounded out the top five locations on school grounds with the highest victim count.

As of June 19, 116 school shooting incidents were recorded in K-12 schools in the United States in 2025. Within the provided time period, the greatest number of K-12 school shootings was recorded in 2023, at 350. 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.

The School Survey on Crime and Safety (SSOCS) is managed by the National Center for Education Statistics (NCES) on behalf of the United States Department of Education (ED). SSOCS collects extensive crime and safety data from principals and school administrators of public schools in America. Data from this collection can be used to correlate school characteristics with violent and serious violent crimes in American schools. Furthermore, data from SSOCS can be used to assess what school programs, practices, and policies are used by schools in their efforts to prevent crime. SSOCS has been conducted three times, in school years 1999-2000, 2003-2004, and 2005-2006. The 1999-2000 School Survey on Crime and Safety (SSOCS:2000) was developed by the National Center for Education Statistics (NCES) and conducted by Abt Associates Inc. Funding for the survey was provided by the Office of Safe and Drug Free Schools. Questionnaire packets were mailed to 3,366 public primary, middle, high, and combined schools. A total of 2,270 public schools submitted usable questionnaires for a weighted response rate of 70 percent. Data were collected from March 27, 2000 to August 15, 2000.

In 2021, around 3.2 percent of students of Asian descent in the United States reported being the victim of a threat or injury with a weapon at school. In the same year, 8.5 percent of students belonging to two or more races reported being threatened or injured with a weapon at school.

As of March 19, ***** school shootings were recorded in the United States in 2025, impacting K-12 school grounds and college campuses nationwide. In comparison, there were ** school shooting incidents recorded in 2024. In addition to schools, gun-related violence occurs in many public places within the United States, including workplaces, churches, restaurants, and nightclubs. The source defines school shootings as incidents of gun violence which occurred on school property 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.

The number of homicides of youth ages 5 to18 years old at school in the United States has fluctuated since 1992. During the school year 2019-20, 11 youths aged between five and 18 years old were the victims of a homicide, in which the fatal injury occurred on the campus of a elementary, middle, or high school.

In 2021, about 2.2 out of every 1,000 students between 12 and 14 years of age in the United States were victims of theft. For students between the ages of 15 and 18, this rate was slightly lower, at 0.9 per 1,000 students.

As of September 4, eight people were killed in mass shootings in the United States in 2024. A total 1,159 victims were fatally injured during mass shootings in the United States between 1982 and September 4, 2024.

Between 1966 and June 19, 2025, students were the most likely offenders of K-12 school shootings in the United States, accounting for 42.8 percent of the shootings that took place in elementary and secondary schools. Within the provided time period, almost three percent of K-12 school shootings were perpetrated by a parent, while 3.6 percent were committed by a former student. 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.

As of July 22, 2024, there have been a total of 270 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 225 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 1999 to January 2025, *** school shootings were recorded in the United States, *** of which occurred in public schools. Within the provided time period, only ** shootings were recorded in private schools.

Between 1970 and June 16, 2020, 175 school shootings were perpetrated by 17-year-olds. 16-year-olds perpetrated the second highest number of school shootings, with 163 shootings.

From school years 2009-10 to 2018-19, K-12 school shootings which occurred outside of the school building were most likely to be a dispute or grievance related in the United States, at 43 percent. A dispute or grievance between the victim and the shooter may include situations such as an escalation of an argument or retaliation for bullying. In comparison, 31 percent of school shootings which occurred inside the school building were accidental while 28 percent were school-targeted, meaning the shooting was generally targeted towards school staff or students on school premises, but without a specific victim. The source defines a school shooting as 'any time a gun is fired on school grounds, on a school bus, or during a school event - during school hours or a school event or immediately before or after school hours or school event - including all incidents that meet the criteria above, including accidents and suicides, regardless of intent.'

There were public mass shootings in the United States in every year between 1998 and 2019, resulting in a total of almost 1,900 casualties. When compared with the number of victims of mass shootings in all other developed nations (based on UN specifications), the United States' figure is often higher than all of these countries combined. There were notable exceptions, such as the attacks in Paris on the evening of November 13. 2015, which resulted in 130 deaths and 416 injuries (the same year the Charlie Hebdo shooting killed 12 people and injured 11 more), the 2011 attacks in Oslo and Utøya, Norway and Liège, Belgium which had a combined casualty count of 240 due to gunfire. In the United States, the deadliest mass shooting in this time was the Las Vegas Strip massacre in 2017.

Between 1966 and June 19, 2025, 513 school shootings took place during morning classes. During this same time period, 342 school shootings took place during afternoon classes. The source defines a shooting as any time a gun is brandished, fired, or a bullet hits school property for any reason, regardless of the number of victims, time, or day of week, including gang shootings, domestic violence, shootings at sports games and after hours school events, suicides, fights that escalate into shootings, and accidents.

Between 1966 to June 19, 2025, 40.9 percent of school shootings in the United States resulted in the shooter fleeing and escaping. Within the provided time period, a similar share of school shootings ended with the shooter fleeing and being apprehended, at 35.6 percent. In comparison, only 7.8 percent of school shootings had an end result of the shooter being apprehended and killed by law enforcement, while 4.9 percent resulted in suicide by the shooter. 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. Data may differ based on what definition is used.