This paper describes the spatio-temporal trends in terrorist incidents in the United States, from 1970 through 2004. Utilizing the Global Terrorism Database (GTD) and ancillary data, we examine both the frequency of incidents and their characteristics: location, target type, attack type, weapon type, and perpetrator group. While the frequency of terrorist incidents has declined since the 1970s, there still is significant activity nationwide. Instead of urban-rural or West Coast-East Coast divisions, the pattern is a more complex mosaic based on group identity, target, and weapon type. We conclude that there is an explicit geography of terrorism, one that is quite decentralized and highly localized.
Webb, Jennifer J., and Susan L. Cutter. 2009. "The Geography of U.S. Terrorist Incidents, 1970-2004." Terrorism and Political Violence 21 (July): 428-449. https://www.tandfonline.com/doi/full/10.1080/09546550902950308