Radicalization Clusters? Geographic Concentrations of Violent Extremism and Terrorism in the United States


Project Details


This project is designed to (1) identify geographical areas that have experienced the highest levels of to terrorist violence and extremist crime during the past 20 years; and (2) explore factors that might serve to foster violent extremism.

Primary Findings:

This project involved four related sub-projects:

1. Hot Spots of Terrorism and Other Crimes in the United States, 1970-2008, involving Gary LaFree and Bianca Bersani, identified 65 (out of 3143) counties in the United States which experienced more than 6 terrorist attacks between 1970 and 2008, classifying these counties as “terrorist hot spots.” Among these counties included large urban centers (including Manhattan, Los Angeles, and Miami-Dade) as well as more rural counties (Dakota County NE, Harris County TX). A close look at data on the nature of this terrorist activity reveals that there are different hot spots for far-right terrorism, far-left terrorism, nationalist terrorism, religious terrorism, and single-issue terrorism around the country.

The research team found significant correlations between the frequent occurrence of terrorism and the frequent occurrence of ordinary crimes in counties around the country, but the correlation is not perfect: Terrorism does occur in counties that otherwise experience low rates of criminal activity. Other county-level characteristics significantly and positively related to the occurrence of high levels of terrorism included residential instability and language diversity.

2. Characteristics of American Communities Where Terrorists Lived, Planned, and Conducted Their Attacks, involving Brent Smith, Kevin Fitzpatrick, Paxton Roberts, and Kelly Damphousse: This research involved an exploratory examination of the characteristics of communities in which persons involved in American terrorism over the past 20 years lived, planned, and conducted their activities.  The project focused upon identifying characteristics of U.S. census tracts that provide “markers” that distinguish communities associated with terrorist activities from those unmarked by terrorism. 

Preliminary analysis provides some insight into better understanding the differences and/or similarities among terrorists, terrorist groups, and the communities in which they live and engage in preparatory and terrorist activities. At the most aggregate community level, analysis reveals important regional differences in where terrorist groups live and work. Analyses show very few differences in spatial patterns between Far-Left/Environmental and Far-Right groups—each tends to attack close to where they live. However, International groups demonstrate significant differences between where they “live and work.” Furthermore, these exploratory analyses suggest that certain community characteristics are more salient in determining which communities are more likely to contain terrorists living in, planning in, and targeting specific locations. Region, general socio-demographic, housing, SES, and residential stability characteristics emerge as important elements to differentiating various aspects of terrorist residence, precursor activities, and target locations. 

In many instances these community types differ from typical U.S. communities. Additionally, the research team found important differences between these three types of terrorist groups with regards to where they live and our active both in planning and executing terrorist behaviors. For example, FarLeft/Environmental and Far-Right groups typically reside in communities located in the western United States, with low percentages of foreign-born residents, low percentages of urban residents, lower vacancies, and low percentages of foreign-born residents living in poverty. Comparatively, International groups live predominantly in the northeastern and southern regions of the country, in communities that have large concentrations of foreign-born residents, predominantly reside in urban communities, with lower percentages of married couples with children, owner-occupied housing, and high school graduates.  

3. Examining the Relationship Between the Presence of Hate Groups and the Presence of Violent Far-Right Extremists at the County Level, led by Amy Adamczyk, Steven Chermak, and Joshua Freilich, sought to determine whether the presence of a hate group (including white-supremacist groups and black-supremacist groups) in a county would be significantly related to the likelihood of a far-right terrorist residing in that same county. Analyses established an empirical and statistically significant link between the presence of white hate groups in a county and the residence of a far-right terrorist, providing evidence to support a relationship that had often been assumed.

4. Examining the Relationship Between General Social Survey (GSS) Measures and Far-Right Ideological Violence: A County-level Analysis, led by Amy Adamczyk, Steven Chermak, and Joshua Freilich, used data collected nationally over an eight-year period to identify prevalent attitudes present in counties known to include the residences of far-right terrorists. The research team considered variables from the GSS related to marginalization/integration, economic factors, social capital/trust, social support services, civil liberties, partisanship, religiosity, and social attitudes, and found that, controlling for other factors such as population size, the aggregate level of trust in other people reported by respondents within a community was a significant and negative predictor of the presence of a far-right terrorists’ residence within a community.


Each of the subprojects involved in this study involved bivariate and multivariate statistical analyses. Dependent variables were drawn from existing START- and DHS-funded databases, including the Global Terrorism Database, the American Terrorism Study, and the Extremist Crime Database. 

Independent variables at the county-level were drawn from existing resources, but often had to be compiled to the county level. Data on ordinary crime rates for LaFree and Bersani’s work were drawn from the Uniform Crime Reports, while factors related to county demographics in that project were compiled from the U.S. Census. Smith et al also used Census data to assess the characteristics of counties where terrorists resided, planned, and attacked in the United States. Adamczyk, Chermak, and Freilich compiled information on the presence of hate groups in a county from annual reports assembled by the Southern Poverty Law Center. Data on beliefs and attitudes within counties was aggregated from responses to the U.S. General Social Survey.


Project Period: