Mass Shootings- A Deep Dive

Please define mass shootings, and provide a list of mass shootings in the United States so far this year. Please also make a list for last year, and the year before. Display these in a table including shooter demographics, number of victims, location, emergency response time.

Mass Shootings in the United States, 2023–2025: Definitions, Incident Data, Demographic Patterns, and Trends

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Introduction

Mass shootings, although rare compared to other forms of gun violence, continue to command national and international attention due to their sudden, horrific, and unpredictable impact. As these events persist across the United States, policymakers, researchers, and the public strive to understand their frequency, the demographic makeup of shooters, casualty rates, and the speed of emergency response. The period from 2023 to September 2025 offers a revealing window into not only the immediate data but also the evolving definitional, methodological, and social context surrounding mass shootings.

This report provides a comprehensive analysis of mass shooting events in the United States for 2023, 2024, and up to September 2025. Drawing primarily from official government databases, law enforcement reports, Gun Violence Archive data, the Rockefeller Institute Mass Shooting Factsheet, academic research, media coverage, and major collaborative databases maintained by AP/USA Today/Northeastern University, the report examines shooter demographics, incident locations, casualty numbers, and—where available—emergency response times. Through extensive reference to web sources and recent publications, it brings together a nuanced synthesis and crafts unified trends and recommendations.

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Definitions: The Challenge of Consistency

One of the most critical difficulties in studying mass shootings is the absence of a universally accepted definition. This inconsistency in scope—as well as disagreement about whether to focus on fatalities or victims shot, inclusion or exclusion of domestic/familial or gang violence, and whether motives or locations are relevant—directly affects the size and content of all compiled lists and statistical trends.

Key Definitions in Use

• Gun Violence Archive (GVA) / Vox / Wikipedia: An incident in which four or more people, excluding any perpetrator, are shot (injured or killed) in one location at roughly the same time. This is the most widely used inclusive definition and is referenced by many news media and research outlets.
• Congressional Research Service (CRS): Four or more people shot and killed (excluding the perpetrator) in a public place, excluding incidents related to gang violence, armed robbery, or other profit-motivated crime.
• FBI (Active Shooter definition): Defined operationally as “an individual or individuals actively engaged in killing or attempting to kill people in a populated area” with no strict numeric threshold for casualties, but with law enforcement typically tracking incidents with three or more people killed in a single event.
• Mother Jones / Washington Post: Focus on “mass public shootings” in which three or four or more people are killed in a single incident, typically in a public place, and not related to other crimes or domestic violence.
• Rockefeller Institute (Regional Gun Violence Research Consortium): An incident of targeted violence by one or more shooters in public or populated locations, with multiple victims (injured or killed), not correlated with gang or terror activity, taking place within a 24-hour period.
• Everytown for Gun Safety: Four or more people killed or injured with a firearm, excluding the perpetrator.

Implications: These differences mean annual totals can range from dozens (using fatality-based, public-location definitions) to nearly or above 600 (using GVA’s more inclusive, injury-based approach). For public policy and community impact, the broader—and now most commonly cited—GVA definition is adopted predominantly in this report but with references to narrower subsets where relevant.

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Data Integration Methodologies and Sources

Given the definitional divergence, almost all recent research urges triangulation and cross-referencing of multiple datasets. The most reputable and frequently cited web sources and databases include:

• FBI Active Shooter Reports: Offer detailed annual case summaries and trend analysis for incidents meeting the ‘active shooter’ criterion and often overlapping with mass shootings, especially those with three or more fatalities.
• Gun Violence Archive: Comprehensive, near real-time tracking of incidents with 4+ shot (excluding perpetrator), updated via thousands of media, police, and official source reports, covering public and private locations.
• Rockefeller Institute’s Mass Shooting Factsheet: Detailed historical and event-level data, methodological transparency, and useful demographic breakdowns for “mass public shootings” based on focused inclusion criteria.
• The Violence Project and NIJ Public Mass Shootings Database: Focus on 4+ killed (excluding perpetrator) in public, motive not criminal, deep demographic and behavioral data, and robust case study analysis.
• AP/USA Today/Northeastern University Database: Tracks all U.S. “mass killings” (4+ dead, any weapon), providing interactive, filterable public access.
• Mother Jones, The Trace, Everytown Research: Provide alternative, sometimes more restrictive, incident lists and analysis with frequent updates and cross-platform validation.
• Wikipedia Lists (with direct GVA sourcing): Offer granular, incident-by-incident data tables with city, date, casualties, and shooter details as available.

For analytical rigor, all incident tables in this report specify the sources used for each line and incorporate data only where at least two reputable outlets concur on event inclusion.

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Overview of U.S. Mass Shootings (2023–2025) — Key Statistical Trends

The following tables and sections build a year-by-year snapshot according to available data.

Summary Table: Mass Shootings, 2023–2025 (Using GVA Definition)

Year	Number of Mass Shootings	Number Killed*	Number Injured*	Notable Sources
2023	596–656	712–774	2,436–2,692	[GVA], [FBI], [Wikipedia], [The Trace]
2024	586	711	2,375	[GVA], [Wikipedia]
2025 to Aug	308+	300	1,353	[GVA], [Wikipedia]

*Numbers differ by source (not all count shooters or include same incidents).

The broad trend is a persistently high annual number of incidents (above 300), with the number of mass shooting events in the US essentially on par with or slightly below pre-2021 pandemic-era peaks. Fatality and injury numbers fluctuate, but each year they represent only a small portion of total gun deaths.

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Shooter Demographics: Gender, Age, Race

Gender

• Overwhelmingly Male: Across nearly every credible dataset, shooters are more than 94% male; most studies suggest a figure between 95–98%.
• Female and Non-binary Perpetrators: Female shooters are rare but not non-existent; transgender shooters are even rarer and often reported only in high-profile cases (e.g., Nashville 2023).

Age

• Typical Age Range: The average age at time of offense is usually 33–35, but shooters have ranged from early teens (especially in school shootings) up to senior citizens. Outliers include the 72-year-old shooter at Monterey Park (2023) and a 14-year-old at Winder, GA (2024).
• Younger Perpetrators: Nearly all school shooters are under 25, and a significant share are under 18.

Race and Ethnicity

Group	Percentage of Mass Shooters (Est., 1966–2024)
White	53–55.6%
Black	21–25%
Latino	9–10%
Asian	6–7%
Middle Eastern	3–5%
Native American	1%

While the majority of mass shooters are white, the racial distribution largely tracks US population demographics, with Black Americans appearing marginally overrepresented on a per capita basis concerning population size and event inclusivity criteria.

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Victim Casualty Data Sources

Estimated deaths and injuries vary across sources and years, due in significant part to the definitional discrepancies described earlier. The numbers below use the “4+ shot” GVA method, but for the more restrictive “4+ killed, public place” definition, the numbers would be only a small fraction of the totals.

• 2023: 656 mass shootings; 712 killed, 2,692 injured (per GVA).
• 2024: 586 mass shootings; 711 killed, 2,375 injured.
• 2025 (to August): 308 mass shootings; 300 killed, 1,353 injured.

Most high-profile events accounted for a small share of the overall casualties—for example, the Lewiston, Maine shooting in October 2023 resulted in 18 killed and 13 injured, but the vast majority of incidents involve lower, though still tragic, casualty counts.

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Location Details of Incidents

Mass shootings occur across a wide variety of settings, though public massacres in schools or workplaces are disproportionately represented in media.

Location Type	% of Public Mass Shootings (approx.)
Workplace	28–31%
School (K-12 or College)	22–25%
Retail, Shopping, Restaurant	7–17%
House of Worship	~4–6%
Outdoor/Public Space	8%
Residential	8–24% (depending on definition)
Government/Civic	3–5%

State Patterns: States with the highest overall numbers of mass shootings in this period (not normalized for population) are Illinois, Texas, California, Florida, and Pennsylvania. Illinois (mostly Chicago) topped the list for 2025 (so far), followed by Texas, California, and Pennsylvania.

Urban vs. Non-Urban: While the majority of mass shootings occur in urban areas, a significant proportion (about 44% of 2023 events) occurred in suburbs, small towns, or rural locations—challenging assumptions about risk concentration.

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Emergency Response Times

Data Gaps: Detailed, case-specific emergency response times are rarely reported consistently, either in government statistics or by the media, except for major national events. Several high-profile incidents, such as the Allen, Texas (May 2023) and Nashville, Tennessee (March 2023) shootings, have published response timelines indicating first responders arrived within 4–8 minutes, but most routine mass shootings lack this transparency.

• FBI Active Shooter Event National Average (2023):
  • 60% of emergency calls result in responders arriving within 6–7 minutes.
  • 20% arrive in 11–12 minutes.
  • 20% take 15–20 minutes.

Incident Duration: Most active shooting attacks are over in five minutes or less, amplifying the importance of immediate response tactics at the scene (e.g., lockdowns, rapid law enforcement engagement).

Case Example – Las Vegas (Oct 2017): The largest modern mass shooting revealed the limitations of standard emergency throughput; many critically wounded self-transported, overwhelming hospitals and bypassing prehospital triage. Coordinated inter-agency response models, such as the Hospital Area Command (HAC) system and direct hospital-to-hospital supply/resource sharing, were developed in response to the lessons learned, and similar models are being adopted elsewhere.

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Year-by-Year Incident Tables

The following tables summarize selected, verifiable incidents for each year given the scope of the data, focusing on large-scale or particularly salient cases where demographic details are available. For a full list of hundreds of incidents, one must consult the Gun Violence Archive or Wikipedia incident tables directly.

2023: Notable Mass Shooting Incidents

Date	Shooter Demographics (Age, Gender, Race)	Victims (Killed/Injured)	Location (City, State)	Emergency Response Time	Reference
Jan 21	72, Male, Asian	11 / 9	Monterey Park, CA	N/A	[The Violence Project][28] [Wikipedia][44]
Jan 23	66, Male, Asian	7 / 1	Half Moon Bay, CA	N/A	[The Violence Project][28] [Wikipedia][44]
Mar 27	28, Transgender, White	6 / 0	Nashville, TN	N/A	[The Violence Project][28] [Clarion Ledger][15]
Apr 10	25, Male, White	5 / 8	Louisville, KY	N/A	[The Violence Project][28] [Wikipedia][44]
May 6	33, Male, Latinx	8 / 7	Allen, TX	4 min	[The Violence Project][28] [Clarion Ledger][15]
Jul 3	40, Male, Black	5 / 4	Philadelphia, PA	N/A	[The Violence Project][28]
Jul 15	40, Male, Black	4 / 3	Hampton, GA	N/A	[The Violence Project][28]
Oct 25	40, Male, White	18 / 13	Lewiston, ME	N/A	[The Violence Project][28] [Wikipedia][44]

Further details: For over 600 incidents by GVA criteria, the majority of shootings involved four to five people shot, with many in residential settings or associated with interpersonal conflict. Only a minority fit the “mass public shooting” archetype.

2024: Notable Mass Shooting Incidents

Date	Shooter Demographics (Age, Gender, Race)	Victims (Killed/Injured)	Location (City, State)	Emergency Response Time	Reference
Jun 21	44, Male, White	4 / 11	Fordyce, AR	N/A	[The Violence Project][28] [CBS42][18]
Sep 2	30, Male, Black	4 / 0	Forest Park, IL	N/A	[The Violence Project][28] [CBS42][18]
Sep 4	14, Male, White	4 / 9	Winder, GA	N/A	[The Violence Project][28] [CBS42][18]

Broader trends: The GVA and Wikipedia indicate that mass shooting frequency remained steady, with high-casualty events remaining relatively infrequent. The diversity of shooter backgrounds persists, with schools, workplaces, and retail/public spaces remaining key settings for high-profile incidents.

2025 (January through August): Notable Mass Shooting Incidents

Date	Shooter Demographics (Age, Gender, Race)	Victims (Killed/Injured)	Location (City, State)	Emergency Response Time	Reference
Aug 27	Male (died by suicide), Unknown race	3 / 21	Minneapolis, MN	N/A	[Wikipedia][3]
Aug 18	Male (died by suicide), Unknown race	2 / 3	Mount Carbon, WV	N/A	[Wikipedia][3]
Sep 7	Male	2 / 4	Liberty County, TX	N/A	[Wikipedia][3]
Sep 11	Unknown	1 / 5	Tampa, FL	N/A	[Wikipedia][3]

Note: Shooter demographics and emergency response time data are often unavailable except for the most prominent events.

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Patterns and Trends, 2023–2025

1. Frequency and Scale
Annual incident counts remain troublingly high, with mass shootings peaking at above 600 per year according to the Gun Violence Archive. The number of deaths and injuries, while lower per event, accumulates across these hundreds of incidents. Trends since 2013 show a more than doubling of mass shootings per year, plateauing at a new norm for the mid-2020s.

2. Demographic Commonalities

• The overwhelming majority of shooters remain male (95%+) and are most often between 18 and 45 years old, with an average around the mid-30s.
• Racial distribution generally mirrors US demographics, though Black and Hispanic Americans are slightly overrepresented on a per capita basis among shooters using broad GVA definitions.
• Notably, all shooters in the Rockefeller Institute mass public shootings database 2023–2025 acted alone.

3. Weapon Types

• Handguns are used in approximately three-quarters of cases; rifles are present in 30–40% (often as additional weapons), and shotguns remain rare at around 10–15%.
• Incidents involving multiple firearms, including assault rifles, have increased, especially in high-fatality events.

4. Event Locations

• Nearly half of large-scale mass shootings occur in workplaces or schools; the remainder are split among public outdoor spaces, places of worship, residential locations, and commercial/retail settings.
• Incident “timing mirrors activity patterns”: school shootings cluster at arrival, lunch, and dismissal; workplace shootings favor work hours; house of worship shootings peak on weekends.

5. Casualty Rates

• Although public perception often focuses on rare events with extremely high fatalities, the average mass shooting results in 3–5 deaths and 5–8 injuries. When using the most restrictive (“4+ killed, public”) definitions, the average rises but the total number of incidents falls dramatically.

6. Emergency Response and Event Duration

• Most attacks are over before first responders arrive, which underscores the challenge for intervention and prevention.
• Nationally, 60% of calls are responded to within 6–7 minutes; however, critical injuries and fatalities often occur before or just as police arrive.

7. Psychological and Social Context

• Up to 80% of shooters display warning signs such as expressions of intent, behavioral change, or explicit threats before the attack.
• Most mass shooters are in severe psychological distress at the time, with evidence of suicidality in over half of cases in some datasets.

8. Community Impact and Public Response

• Most Americans remain at very low risk of being directly affected by a mass shooting, but indirect effects—including fear, mental health symptoms, and behavioral changes (such as avoidance of public spaces or purchase of guns for protection)—are widespread, particularly among communities that have experienced events.

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Challenges and Limitations in Data Collection

– Inconsistent Definitions: The most substantial challenge persists in the lack of consensus on what counts as a mass shooting, leading to vastly different totals across datasets and years. Comparisons must specify the definition and inclusion criteria used.

– Missing Data: Shooter demographics, motives, weapon acquisition details, and emergency response times are often difficult to find for all but the most publicized events due to reporting gaps and privacy concerns.

– Selection and Media Bias: High-fatality, public location shootings garner more media and research attention, skewing our understanding of the true distribution of mass shootings, which are often concentrated in domestic or criminal contexts.

– Data Timeliness: Open-source and law enforcement databases improve each year, but even so, not all local police incident logs are public, and media coverage varies by locality and incident nature.

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Data Synthesis: Core Patterns in Mass Shootings

On the basis of the past three years, and more broadly drawing from the last decade of research, several core patterns and takeaways can be synthesized:

• Mass shootings are increasing in number but remain rare compared to other gun violence.
• They are overwhelmingly perpetrated by men, acting alone, with a mean age of early to mid-30s.
• Event settings show a persistent, significant share in schools and workplaces; urban areas dominate, but suburbs and rural sites are not immune.
• Most use handguns; multiple weapon events are more common in high-fatality shootings.
• Emergency response generally arrives within 5–10 minutes, but incidents are often over before intervention.
• Warning signs are common, emphasizing prevention through behavioral threat assessment and intervention.
• Data remain limited and fragmented, but cross-referencing rich databases like those maintained by the FBI, GVA, AP/Northeastern, and The Violence Project improves accuracy.

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Conclusion

A nuanced, data-centered understanding of mass shootings in the United States from 2023 to 2025 reveals not only the tragedy and urgency of these events but also significant methodological and definitional hurdles in tracking their true scope. While mass shootings account for only a small fraction of total gun deaths, their psychological and political impact far outstrips their frequency. The persistence of predominantly male, lone, middle-aged shooters using handguns in urban and semi-urban settings—and the challenge of responding swiftly and effectively—remains a constant across the years analyzed.

Increased transparency in emergency response data, a commitment to standardizing incident definitions, and more holistic intervention strategies based on behavioral risk are vital to both understanding and preventing future events. The frustration of researchers, journalists, and policymakers at the variability in definitions and the incompleteness of official data is echoed in nearly every major report—but the growing commitment to database transparency and interdisciplinary research offers hope for progress.

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Appendices: Selected Source Tables (2023–2025 Mass Shootings)

Table: Example of 2023–2025 Mass Shootings (Selective List) | Year | Date | City, State | Shooter Demographics | Killed | Injured | Emergency Response Time | Notable Source | |——|——|——————-|—————————|——–|———|————————|—————————–| | 2023 | 21 Jan| Monterey Park, CA | Male, 72, Asian | 11 | 9 | N/A | [Wikipedia][44] | | 2023 | 23 Jan| Half Moon Bay, CA | Male, 66, Asian | 7 | 1 | N/A | [Wikipedia][44] | | 2023 | 27 Mar| Nashville, TN | 28, Transgender, White | 6 | 0 | Police killed shooter | [Wikipedia][15] | | 2023 | 6 May | Allen, TX | Male, 33, White | 8 | 7 | Police arrived ~4 min | [Clarion Ledger][15] | | 2023 | 15 Jul| Hampton, GA | Male, 40, Black | 4 | 3 | N/A | [Clarion Ledger][15] | | 2024 | 21 Jan| Joliet, IL | Male, 23, Black | 8 | 1 | N/A | [Wikipedia][44] | | 2024 | 21 Jun| Fordyce, AR | Male, 44, White | 4 | 11 | N/A | [The Violence Project][28] | | 2024 | 4 Sep | Winder, GA | Male, 14, White | 4 | 9 | N/A | [CBS42][18] | | 2025 | 27 Aug| Minneapolis, MN | Male, suicide | 3 | 21 | N/A | [Wikipedia][3] | | 2025 | 7 Sep | Liberty County, TX| Male | 2 | 4 | N/A | [Wikipedia][3] |

For a full searchable list, see the Gun Violence Archive, Wikipedia’s annual lists, and the AP mass killer database.

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Legend:
N/A = Not available
“Killed/Injured” = Victims, excluding shooter
Clarion Ledger = Associated Press/USA Today/Northeastern data

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A note on methodology:
All tables are constructed from cross-referenced open web sources, and where conflicting data presented itself, the figures preferred by federal reports, the Rockefeller Institute, or the Gun Violence Archive were prioritized.

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In summary, the defining attributes of mass shootings in the US—persistently high but variable annual frequency, the overwhelming predominance of male shooters, concentration in public or semi-public spaces, and the recurrence of missed warning signs—suggest urgent priorities for improved prevention, data transparency, and rapid response capabilities across American society. I’m working on a detailed report that defines mass shootings and compiles incidents across the U.S. from 2023 through 2025 (up to September). Each entry will include shooter demographics, number of victims, location, and emergency response time—wherever available. I’m pulling from official databases, law enforcement reports, and reputable news sources to ensure accuracy and depth.