What Does Four Decades of Terrorism in the U.S. Look Like?


Editor’s note: We’ve partnered with the National Consortium for the Study of Terrorism and Responses to Terrorism (START) to publish a series of infographics based on data from their Global Terrorism Database and related START projects. Each week we’ll release a new set of graphics that depict trends in global terrorism activity. Sign up for the War on the Rocks newsletter to make sure you don’t miss any of them!

These graphics were designed by Michael Jensen and William Kammerer.


The last two weeks we published infographics that depicted the nature of the terrorist threat in two regions: Latin America and Southeast Asia. This week, we turn our attention toward home and visualize the shape of terrorist activity in the United States since 1970.* Click each graphic to enlarge it.

The first graphic is a map on which all terrorist attacks over more than four decades have been plotted, with the size of the circle reflecting the number of casualties from each attack. [Note: Mass casualty attacks (60+ victims killed or injured) have been given extra weight to make them more clearly visible on the map.]

START Infographic 8-1 - Terrorism in the US 1970-2013

The second graphic depicts two sets of data: total number of attacks by year, and average attack lethality by year. Additionally, the table in the graphic shows where the U.S. ranks among countries that have suffered the most terrorist attacks since 1970. Placing these data on the same chart provides a visual reminder that the metrics by which we define the terrorist threat matter. The 9/11 attacks made 2001 an outlier in terms of attack lethality. But by total attack numbers, 2001 is on the low end, with less than ten percent of the number of attacks in 1970. The United States has historically been an active country in terms of terrorist attack numbers, but the majority of these have been non-lethal.

START Infographic 8-2 - Terrorism in the US-Attacks and Average Lethality 1970-2013

Graphic three breaks down the total attacks from 1970-2013 by state. A disproportionate share of attacks occurred in California and New York. Perhaps more surprising is that both Washington and Oregon fall into the top seven. Alaska, Kentucky, and Rhode Island rank last in terms of attack numbers.

START Infographic 8-3 - Terrorism in the US-Attacks by State-District 1970-2013

The last graphic consist of two charts, the first of which breaks down the total attacks by type. The second displays the percentage of attacks against various types of target. Nearly half (49%) of all attacks over the period in question were bombings. As the second chart shows, those attacks were directed more frequently against facilities than people (and were thus typically non-lethal).

START Infographic 8-4-2 - Terrorism in the US-Attack Types and Target Types 1970-2013


*The data for 1993 are missing from the GTD.  That year is excluded from the analysis.



This graphic is based on preliminary data that is subject to change.  2013 GTD data is not yet available for public download or distribution. It will be released via the GTD website later this summer.

Beginning with 2012 data collection, START made several important changes to the GTD collection methodology, improving the efficiency and comprehensiveness of the process. In general, comparisons of aggregate statistics over time and between locations should be interpreted with caution due to these methodological improvements, as well as the considerable variation in the availability of source materials.


Michael Jensen is the data collection manager for the Global Terrorism Database at START.

John Amble is the Managing Editor of War on the Rocks.