Twenty.
That’s the number of mass shootings in California this year, shootings that have left people injured and killed in numerous cities across the state.
That’s according to data from the Gun Violence Archive, an independent research and data collection organization that’s been around for over a decade. It comes as Americans are reeling from numerous incidents of gun violence in recent days, from a shooting at a Colorado high school that left two students injured and the suspect dead from self-inflicted injuries to the highly publicized fatal shooting of Charlie Kirk — both of which happened to occur on the same day.
What is considered a mass shooting? There’s no one definition
As the nonpartisan Congressional Research Service noted late last year, there is no “single, widely accepted definition” of a mass shooting. The FBI reports on the number of shootings it designates as active shooter incidents, defined as “one or more individuals actively engaged in killing or attempting to kill people in a populated area.” The Gun Violence Archive defines a mass shooting as an event in which four or more people are shot and/or killed a single incident, not including the shooter. It’s that “purely statistical threshold” used by the Gun Violence Archive to define a mass shooting that they say explains why their numbers may be higher than other sources.
Scholars with the Regional Gun Violence Research Consortium at the Rockefeller Institute of Government, a public policy think tank, wrote about the challenges of the varying definitions of mass shootings in July. The authors said that when the phrase “first appeared consistently in the public discourse, it was used to describe a specific subset of firearm violence — premeditated, predatory shootings that had widespread impacts in the locations and broader communities in which they occurred.” They pointed to Columbine High School shooting in 1999, saying it’s the most well-known example, then and largely now.
“Over time, however, the phrase ‘mass shooting’ began to be more loosely applied to any multi-victim incident of gun violence,” the authors said. “As a result, incidents that bore little contextual resemblance to Columbine beyond multiple victims (either injured or killed, depending on the source) were being treated synonymously with this archetypal case.”
The authors gave examples, including shootings that resulted of an escalating altercation or a “family annihilation” in a private residence.
“Although these different types of shootings are each tragic and prevention of similar incidents in the future should be a priority, their qualitative and contextual differences are important to consider in order to identify the respective policies and practices necessary to achieve such an end,” the authors said.
Among how the Rockefeller Institute of Government defines a mass shooting is that it must be carried out at “public or populated locations” with the victims and locations chosen “either at random or for their symbolic value.”
How many mass shootings in the U.S. in 2025? See one figure
There have been 301 mass shootings in America this year, according to Gun Violence Archive’s figures as of Friday, Sept. 12. In 2024, there were 503 mass shootings, according to the Gun Violence Archive.
What state has the most mass shootings? Two states have higher numbers than California
Sorting through Gun Violence Archive Data for 2025 shows how many mass shootings have been recorded in each state. States with higher numbers than California so far this year are Texas at 23 and Illinois at 22.
Paris Barraza is a trending reporter covering California news at The Desert Sun. Reach her at pbarraza@gannett.com.
This article originally appeared on Palm Springs Desert Sun: How many mass shootings have there been in California? See one figure for 2025
Reporting by Paris Barraza, Palm Springs Desert Sun / Palm Springs Desert Sun
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