THIS DATASET WAS LAST UPDATED AT 7:11 AM EASTERN ON DEC. 1

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.

Context

1 in 4 mass shooting victims were children and teens. In the years between 2009 and 2020, the horrific scenes of mass shootings have haunted the nation’s collective conscience.US states with weaker gun laws and higher gun ownership rates have higher rates of mass shootings. Mass shooting is defined as any incident in which four or more people are shot and killed, excluding the shooter. The number of mass shootings that plague this country is far too high, and the counts are just a small fraction of the lives left forever changed after the tragedy of a mass shooting. So here is the data for list of mass shootings in United States from 2018 - 2022.

Content

This dataset has five csv files of years 2018 - 2022. Each data contains following attributes - Date : The date on which the mass shooting incident happened - State : The state where the incident took place - Dead : total number of people died in mass shooting - Injured: total number of people who got injured in mass shooting- - Total : total of dead and injured people - Description : description/short report of the incident which may include information like gender/place etc. Data for 2022 Mass shootings will be updated every 15 days!

Acknowledgements

This data was scraped from https://en.wikipedia.org/wiki/List_of_mass_shootings_in_the_United_States using BeautifulSoup.

Image banner by Wall Street Journal

Inspiration

• EDA and Viz.
• Which state has highest number of mass shootings
• Contextual analysis of the description column
• Trend of mass shooting in past years
• Number of people killed/injured on an average in a month.

Check out my other works

• Datasets
• Notebooks

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 Washington Post spent a year determining how many children have been affected by school shootings, beyond just those killed or injured. To do that, reporters attempted to identify every act of gunfire at a primary or secondary school during school hours since the Columbine High massacre on April 20, 1999. Using Nexis, news articles, open-source databases, law enforcement reports, information from school websites, and calls to schools and police departments, The Post reviewed more than 1,000 alleged incidents, but counted only those that happened on campuses immediately before, during or just after classes.

Shootings at after-hours events, accidental discharges that caused no injuries to anyone other than the person handling the gun, and suicides that occurred privately or posed no threat to other children were excluded. Gunfire at colleges and universities, which affects young adults rather than kids, also was not counted.

After finding more than 200 incidents of gun violence that met The Post’s criteria, reporters organized them in a database for analysis. Because the federal government does not track school shootings, it’s possible that the database does not contain every incident that would qualify.

To calculate how many children were exposed to gunfire in each school shooting, The Post relied on enrollment figures and demographic information from the U.S. Education Department, including the Common Core of Data and the Private School Universe Survey. The analysis used attendance figures from the year of the shooting for the vast majority of the schools.

The Post’s database is updated regularly as school shootings are reported and as facts emerge about individual cases. The Post is seeking assistance in making the database as comprehensive as possible. To provide information about school shootings since Columbine that fit The Post’s definition, send us an email at schoolshootings@washpost.com.

Number and percentage of homicide victims, by type of firearm used to commit the homicide (total firearms; handgun; rifle or shotgun; fully automatic firearm; sawed-off rifle or shotgun; firearm-like weapons; other firearms, type unknown), Canada, 1974 to 2018.

BackgroundSeveral past studies have found that media reports of suicides and homicides appear to subsequently increase the incidence of similar events in the community, apparently due to the coverage planting the seeds of ideation in at-risk individuals to commit similar acts.MethodsHere we explore whether or not contagion is evident in more high-profile incidents, such as school shootings and mass killings (incidents with four or more people killed). We fit a contagion model to recent data sets related to such incidents in the US, with terms that take into account the fact that a school shooting or mass murder may temporarily increase the probability of a similar event in the immediate future, by assuming an exponential decay in contagiousness after an event.ConclusionsWe find significant evidence that mass killings involving firearms are incented by similar events in the immediate past. On average, this temporary increase in probability lasts 13 days, and each incident incites at least 0.30 new incidents (p = 0.0015). We also find significant evidence of contagion in school shootings, for which an incident is contagious for an average of 13 days, and incites an average of at least 0.22 new incidents (p = 0.0001). All p-values are assessed based on a likelihood ratio test comparing the likelihood of a contagion model to that of a null model with no contagion. On average, mass killings involving firearms occur approximately every two weeks in the US, while school shootings occur on average monthly. We find that state prevalence of firearm ownership is significantly associated with the state incidence of mass killings with firearms, school shootings, and mass shootings.

Mass shootings occur with horrifying frequency in the United States. Many point to electoral politics as a potential path to change this. Here, we test whether mass shootings increase electoral participation using the most granular dataset to date. We draw information on mass shootings from the Gun Violence Archive and estimate national block group-level turnout using 4 snapshots of the national voter file. Using a regression discontinuity in time design, we find that mass shootings mobilize local voters (especially in heavily Democratic areas), but do not shift presidential vote choices. Further, we show that pre-election mass shootings were associated with increased support for a 2016 Californian gun reform ballot initiative. Our results show the (geographically-bounded) salience of mass shootings for local political engagement and ballot reform efforts.

https://www.youtube.com/watch?v=A8syQeFtBKc

Context

The Stanford Mass Shootings in America (MSA) is a dataset released under Creative Commons Attribution 4.0 international license by the Stanford Geospatial Center. While not an exhaustive collection of mass shootings, it is a high-quality dataset ranging from 1966 to 2016 with well-defined methodology, definitions and source URLs for user validation.

This dataset can be used to validate other datasets, such as us-mass-shootings-last-50-years, which contains more recent data, or conduct other analysis, as more information is provided.

Content

This dataset contains data by the MSA project both from it's website and from it's Github account. The difference between the two sources is only on the data format (i.e. .csv versus .geojson for the data, or .csv versus .pdf for the dictionary).

• mass_shooting_events_stanford_msa_release_06142016
  • Contains a nonexaustive list of US Mass Shootings from 1966 to 2016 in both .csv and .geojson formats.
• dictionary_stanford_msa_release_06142016
  • Contains the data dictionary in .csv and .pdf formats. Note the .pdf format provides an easier way to visualize sub-fields.

Note the data was reproduced here without any modifications other than file renaming for clarity, the content is the same as in the source.

The following sections are reproduced from the dataset creators website. For more details, please see the source.

Project background

The Stanford Mass Shootings of America (MSA) data project began in 2012, in reaction to the mass shooting in Sandy Hook, CT. In our initial attempts to map this phenomena it was determined that no comprehensive collection of these incidents existed online. The Stanford Geospatial Center set out to create, as best we could, a single point repository for as many mass shooting events as could be collected via online media. The result was the Stanford MSA.

What the Stanford MSA is

The Stanford MSA is a data aggregation effort. It is a curated set of spatial and temporal data about mass shootings in America, taken from online media sources. It is an attempt to facilitate research on gun violence in the US by making raw data more accessible.

What the Stanford MSA is not

The Stanford MSA is not a comprehensive, longitudinal research project. The data collected in the MSA are not investigated past the assessment for inclusion in the database. The MSA is not an attempt to answer specific questions about gun violence or gun laws.

The Stanford Geospatial Center does not provide analysis or commentary on the contents of this database or any derivatives produced with it.

Data collection methodology

The information collected for the Stanford MSA is limited to online resources. An initial intensive investigation was completed looking back over existing online reports to fill in the historic record going back to 1966. Contemporary records come in as new events occur and are cross referenced against a number of online reporting sources. In general a minimum of three corroborating sources are required to add the full record into the MSA (as many as 6 or 7 sources may have been consulted in many cases). All sources for each event are listed in the database.

Due to the time involved in vetting the details of any new incident, there is often a 2 to 4 week lag between a mass shooting event and its inclusion in the public release database.

It is important to note the records in the Stanford MSA span a time from well before the advent of online media reporting, through its infancy, to the modern era of web based news and information resources. Researchers using this database need to be aware of the reporting bias these changes in technology present. A spike in incidents for recent years is likely due to increased online reporting and not necessarily indicative of the rate of mass shootings alone. Researchers should look at this database as a curated collection of quality checked data regarding mass shootings, and not an exhaustive research data set itself. Independent verification and analysis will be required to use this data in examining trends in mass shootings over time.

Definition of Mass Shooting

The definition of mass shooting used for the Stanford database is 3 or more shooting victims (not necessarily fatalities), not including the shooter. The shooting must not be identifiably gang, drug, or organized crime related.

Acknowledgements

The Stanford Mass Shootings in America (MSA) is a dataset released under [Creative Commons Attribution 4.0 int...

List of the most notable mass shootings in the United States that have occurred since 1920. Only shootings that have Wikipedia articles of their own are included in this list. Detailed lists of mass shootings can be found per year at their respective pages. Larger documentation of mass shootings in the United States has occurred through independent and scholarly studies such as the Stanford University Mass Shootings in America Data Project: https://library.stanford.edu/projects/mass-shootings-america

UPDATES WEEKLY

US Mass Shootings, 1982–2023: Data From Mother Jones’ Investigation

The full data set from our in-depth investigation into mass shootings.

This database originally covered cases from 1982 to 2012 and has since been updated and expanded numerous times. For analysis and context on this data—including how we built the database, and a change to the baseline for victim fatalities with cases dating from January 2013—see our Guide to Mass Shootings in America, which includes an interactive map documenting all of the cases.

Source: https://www.motherjones.com/politics/2012/12/mass-shootings-mother-jones-full-data/

Source: https://www.gunviolencearchive.org/reports/mass-shooting

Compiled with month and year added to each record. Wanted to understand how often these occur.

Collection Methodology

All data was downloaded from the K-12 School Shooting Database (K-12 SSDB), which comprehensively compiles documents when a gun is brandished, is fired, or a bullet hits school property for any reason, regardless of the number of victims, time of day, or day of week. Simple excel querying was then done to separate the multiple sheets in the downloaded file. If you are interested, it is highly advisable to go over their research methodology to understand how they conduct research and compile the data from multiple data sources - Link to the Database: https://www.chds.us/ssdb/ - Research Methodology: https://www.chds.us/ssdb/methods/

Content

The dataset is structured as a relational database (compilation of multiple sheets) referenced with a unique incident ID number that links to the corresponding INCIDENT, SHOOTER, VICTIM, and WEAPON files. - INCIDENT: Incident ID number and the information related to the what, where, and when the shooting happened. - SHOOTER: Incident ID number and details about the shooter. Multiple rows that have similar incident ID numbers indicate multiple shooters involved. - VICTIM: Incident ID number and details about the victim. Multiple rows have the same incident ID number if there were multiple victims.
- WEAPON: Incident ID number and details about the weapon used (including weapons that were possessed by the shooter during the incident but were not fired). Multiple rows have the same incident ID number if there were multiple weapons used.

Limitation

Due to my limited skill and expertise in data scraping, I couldn't find a way to automate the data scraping workflow on this dataset. My initial plan was like so in an attempt to create a dashboard out of it. I will leave that as a room for improvement for you.

Context

There's currently a lack of large and easily-accessible amounts of detailed data on gun violence.

Content

This project aims to change that; we make a record of more than 260k gun violence incidents, with detailed information about each incident, available in CSV format. We hope that this will make it easier for data scientists and statisticians to study gun violence and make informed predictions about future trends.

The CSV file contains data for all recorded gun violence incidents in the US between January 2013 and March 2018, inclusive.

Acknowledgements

Where did you get the data?

The data was downloaded from gunviolencearchive.org. From the organization's description:

Gun Violence Archive (GVA) is a not for profit corporation formed in 2013 to provide free online public access to accurate information about gun-related violence in the United States. GVA will collect and check for accuracy, comprehensive information about gun-related violence in the U.S. and then post and disseminate it online.

How did you get the data?

Because GVA limits the number of incidents that are returned from a single query, and because the website's "Export to CSV" functionality was missing crucial fields, it was necessary to obtain this dataset using web scraping techniques.

Stage 1: For each date between 1/1/2013 and 3/31/2018, a Python script queried all incidents that happened at that particular date, then scraped the data and wrote it to a CSV file. Each month got its own CSV file, with the exception of 2013, since not many incidents were recorded from then.

Stage 2: Each entry was augmented with additional data not directly viewable from the query results page, such as participant information, geolocation data, etc.

Stage 3: The entries were sorted in order of increasing date, then merged into a single CSV file.

Inspiration

I believe there are plenty of ways this dataset can be put to good use. If you have an interesting idea or feel like messing around with the data, then go for it.

I was originally inspired to compile it in the wake of the Parkland shooting and the mass media coverage that followed. Reports like this and this showed that Nikolas Cruz had exhibited plenty of warning signs on social media before the shooting; what if we could build a machine learning system that preemptively detected such signs?