U.S. Terrorism Incidents Dataset

The U.S. Terrorism Incidents Dataset from CSIS’s Warfare, Irregular Threats, and Terrorism Program catalogs terrorist attacks and disrupted plots in the United States, with full coding methodology, codebook, and downloadable data.

The U.S. Terrorism Incidents Dataset is maintained by the Warfare, Irregular Threats, and Terrorism Program (WITT) at the Center for Strategic and International Studies (CSIS). It catalogs terrorist attacks and disrupted plots in the United States. Coding terrorism involves unavoidable judgment calls. For a discussion of some of the methodological challenges this dataset confronts, see "The Difficulty of Coding Terrorism." WITT's definitions and coding rules have been refined over time, and figures cited in earlier CSIS analyses may not be replicable using the current dataset. Full criteria and definitions are detailed in the methodology and codebook below.

Dataset: 260527_WITT_Terrorism_Dataset.xlsx 
Methodology: 260527_WITT_Terrorism_Methodology.pdf
Codebook: 260527_WITT_Terrorism_Codebook.pdf

Recommended citation:

Warfare, Irregular Threats, and Terrorism Program, U.S. Terrorism Incidents Dataset, version 260527 (Washington, DC: Center for Strategic and International Studies, May 2026), https://www.csis.org/programs/warfare-irregular-threats-and-terrorism-program/us-terrorism-incidents-dataset.

For inquiries about the dataset, contact [email protected].

©2026 Center for Strategic and International Studies. This dataset may be used for research, journalism, and educational purposes with proper citation.

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All U.S. Terrorism Incidents Dataset Content

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The Terrorist Threat to the 2026 World Cup

The 2026 World Cup will be the largest sporting event ever held and a magnet for terrorists of all stripes. A new CSIS brief examines who might attack, what targets are at greatest risk, and the countermeasures being deployed.

Brief by Daniel Byman and Riley McCabe — May 27, 2026

Global Terrorism Threat Assessment 2026

Terrorism is currently declining as a U.S. national security priority, and resources available for counterterrorism are decreasing accordingly. At the same time, uncertainty regarding the future of global terrorism is increasing, bringing greater risk of surprise.

Report by CSIS Scholars — May 26, 2026

The Many Faces of Antisemitic Terrorism in the United States

Anti-Jewish violence in America is no longer driven by one ideology alone. Neo-Nazis, jihadists, anti-Israel extremists, and even state-backed actors are converging on the same targets, stretching counterterrorism defenses and redefining domestic security threats.

Commentary by Daniel Byman — May 26, 2026

Questions to Ask After a Terrorist Attack

Confusion reigns after a terrorist attack. Initial reporting is often flawed, and misperceptions endure even after being debunked by experts. Asking the right questions can help policymakers, journalists, and the public distinguish signal from noise, avoid costly overreaction, and prepare for future threats.

Commentary by Daniel Byman — December 16, 2025

Ideological Trends in U.S. Terrorism

The Warfare, Irregular Threats, and Terrorism Program examines the state of terrorism in the U.S., finding left-wing violence has risen in the last decade but from very low levels and still well below historic levels of violence by right-wing and jihadist actors.

Analysis by Daniel Byman and Riley McCabe — September 26, 2025

Global Terrorism Threat Assessment 2025

Terrorism remains a threat to U.S. citizens, assets, and interests despite the national security community’s decreasing focus on counterterrorism.

Report by Alexander Palmer, Riley McCabe, Daniel Byman, and Skyeler Jackson — March 28, 2025