Study: Attacks, Plots by Homegrown Terrorists in the United States Have Increased

Over the past decade, attacks and plots by homegrown terrorists in the United States have increased, the work of extremists from across the political spectrum -- roughly 40 percent of it by so-called "lone wolf," non-aligned actors -- says an analysis by the National Consortium for the Study of Terrorism and Responses to Terrorism (START) based at the University of Maryland.

The statistics underscore the threat addressed in a White House plan released Thursday: Strategic Implementation Plan for Empowering Local Partners to Prevent Violent Extremism in the United States - a blueprint for "building community resilience against violent extremism."

"There have been more than 200 terrorist attacks in the United States since 9/11, but what has really increased is the total number of foiled terrorist plots," says UMD researcher and START director Gary LaFree, who has developed the largest and most comprehensive unclassified terrorism database in the world with funding from the U.S. Department of Homeland Security. "Our researchers have tracked over 100 foiled plots in the past decade. Most of these would be classified as homegrown terrorism."

The new White House plan follows up on a strategy first laid out last August, and discussed at UMD by Secretary of Homeland Security Janet Napolitano in October.

"The facts make it clear - homegrown, violent extremism is not just a problem for other countries," LaFree explains. "The administration plan confronts this reality by providing a strategy that draws heavily on local communities as the key to prevention."

FACT SHEET: VIOLENT EXTREMISM IN THE UNITED STATES

Overall Domestic Terror Stats (from the Global Terrorism Database)

  • Between 2000 and 2010 there were 213 terrorist attacks in the United States. Seventeen of these, including the four 9/11 attacks, were fatal.
  • Since Sept. 11, 2001, 32 people have been killed in terrorist attacks in the United States. The most lethal attack was the 2009 shooting at Ft. Hood in Texas, in which 13 people died.
  • Forty percent of terrorist attacks in the United States since 2000 have involved individuals with no apparent affiliation to a known extremist group. These individuals included adherents of a range of ideologies, including anti-abortion extremists, environmental extremists, White supremacists, and Islamist extremists.
  • Of the attacks in the United States for which perpetrator information is known (73 percent), the groups most frequently launching completed attacks were the Earth Liberation Front (ELF) and the Animal Liberation Front (ALF). High-profile attacks by individuals affiliated with Tehrik-i-Taliban Pakistan (TTP) and al-Qaida in the Arabian Peninsula (AQAP) were successfully foiled.

The Global Terrorism Database is an open-source database including information on more than 98,000 terrorist events around the world from 1970 through 2010. It is currently the most comprehensive unclassified database on terrorist events in the world. For each incident, information is available on the date and location of the incident, weapons used and nature of the target, the number of casualties, and - when identifiable -the group or individual responsible.

Profiles of Islamic Radicalization in North America

START's "Profiles of Islamic Radicalization in North America Database" provides information on 211 individuals known to have radicalized in North America to the point of supporting violence from 1989 to 2011. These homegrown violent extremists started and completed a significant portion of their radicalization in North America, though not all attempted or carried out violence in North America.

  • The vast majority of homegrown Islamist extremists (80 percent) began their radicalization after the events of 9/11 and the subsequent Global War on Terrorism.
  • Nearly half of the identified homegrown Islamist extremists (45 percent) come from a middle class background, and the majority (59 percent) are highly rooted in their host society.
  • At least 24 percent of the individuals included in this study were converts to Islam.

Extremist Crimes

START's "Extremist Crime Database" includes a systematic collection of open-source data on non-violent and violent criminal behavior in the United States associated with far-right extremist groups, far-left extremist groups, and al-Qaida-influenced groups. By developing this database, START researchers have thus far recorded thousands of criminal incidents committed by far-right extremists between 1990 and 2010 and more than one hundred by those inspired by al-Qaida. Data collection on far-left criminal activity is currently underway.

  • More than 345 homicide incidents were committed by at least one far-rightist between 1990 and 2010.
  • Far-rightists killed almost 50 law enforcement officials between 1990 and 2010. These incidents involved federal, state and local police officers, correctional officers, private security guards and one judge.
  • Far-right extremists committed more than 350 "financial schemes" since 1990. Since data collection and coding is ongoing this number will grow.
  • Almost 25 fatal incidents (in which the suspect killed others and/or was killed by police or committed suicide) have been committed by al-Qaida-inspired extremists since 1990.
  • Al-Qaida-inspired extremists committed close to 100 "financial schemes" since 1990.

Featured

  • Improve Incident Response With Intelligent Cloud Video Surveillance

    Video surveillance is a vital part of business security, helping institutions protect against everyday threats for increased employee, customer, and student safety. However, many outdated surveillance solutions lack the ability to offer immediate insights into critical incidents. This slows down investigations and limits how effectively teams can respond to situations, creating greater risks for the organization. Read Now

  • Security Today Announces 2025 CyberSecured Award Winners

    Security Today is pleased to announce the 2025 CyberSecured Awards winners. Sixteen companies are being recognized this year for their network products and other cybersecurity initiatives that secure our world today. Read Now

  • Empowering and Securing a Mobile Workforce

    What happens when technology lets you work anywhere – but exposes you to security threats everywhere? This is the reality of modern work. No longer tethered to desks, work happens everywhere – in the office, from home, on the road, and in countless locations in between. Read Now

  • TSA Introduces New $45 Fee Option for Travelers Without REAL ID Starting February 1

    The Transportation Security Administration (TSA) announced today that it will refer all passengers who do not present an acceptable form of ID and still want to fly an option to pay a $45 fee to use a modernized alternative identity verification system, TSA Confirm.ID, to establish identity at security checkpoints beginning on February 1, 2026. Read Now

  • The Evolution of IP Camera Intelligence

    As the 30th anniversary of the IP camera approaches in 2026, it is worth reflecting on how far we have come. The first network camera, launched in 1996, delivered one frame every 17 seconds—not impressive by today’s standards, but groundbreaking at the time. It did something that no analog system could: transmit video over a standard IP network. Read Now

New Products

  • Compact IP Video Intercom

    Viking’s X-205 Series of intercoms provide HD IP video and two-way voice communication - all wrapped up in an attractive compact chassis.

  • ResponderLink

    ResponderLink

    Shooter Detection Systems (SDS), an Alarm.com company and a global leader in gunshot detection solutions, has introduced ResponderLink, a groundbreaking new 911 notification service for gunshot events. ResponderLink completes the circle from detection to 911 notification to first responder awareness, giving law enforcement enhanced situational intelligence they urgently need to save lives. Integrating SDS’s proven gunshot detection system with Noonlight’s SendPolice platform, ResponderLink is the first solution to automatically deliver real-time gunshot detection data to 911 call centers and first responders. When shots are detected, the 911 dispatching center, also known as the Public Safety Answering Point or PSAP, is contacted based on the gunfire location, enabling faster initiation of life-saving emergency protocols.

  • FEP GameChanger

    FEP GameChanger

    Paige Datacom Solutions Introduces Important and Innovative Cabling Products GameChanger Cable, a proven and patented solution that significantly exceeds the reach of traditional category cable will now have a FEP/FEP construction.