Overview of Mass Casualty Incidents in the US (2015-2025)

Over the past decade, the United States has seen a disturbing rise in mass casualty events – from active shooter incidents and vehicle attacks to targeted assassinations and attempts. Data from sources like the Gun Violence Archive and Wikipedia show hundreds of mass shootings each year. The definition varies slightly across sources, but most classify an event as a mass shooting when four or more people are shot, excluding the perpetrator.

Since 2016, vehicle ramming assaults – often driven by ideology, rage, or personal grievance – have become increasingly common, peaking between 2017 and 2021. Meanwhile, assassination attempts against public figures have risen sharply in the 2020s, fueled in part by growing political polarization and online extremism.

Together, these incidents have claimed thousands of lives and exposed ongoing challenges in gun access, mental health care, extremism prevention, and physical security preparedness.

The following table highlights key examples of these events, organized by type. Each row focuses on incidents with at least four fatalities or significant injuries, providing a clearer look at how these trends have evolved over time.

Major Mass Shootings (Single or Multi-Person)

Mass shootings account for the majority of these events. Between 2015 and 2024 alone, the Gun Violence Archive recorded more than 4,000 incidents, resulting in thousands of deaths. The most devastating attacks often involved high-capacity weapons and targeted public spaces. Below is a selection of the deadliest and most consequential incidents from 2015–2025 (excluding perpetrators in cases of suicide).