Research on the comparative use of concentration camps is limited, even though more than 150 such systems were employed across more than 90 countries between 1896 and 2018, including at least 15 after 2001. This project will produce original new global datasets on concentration camp systems from 1896-2018 that will be made publicly available. The new datasets will facilitate study of the causes, conduct, and consequences of concentration camp systems and therefore will enable new scholarly research that examines the role played by concentration camp systems in contentious politics, government repression, forced migration, and political violence. This project will produce two original datasets on the use of concentration camps globally between 1896 and 2018 in over 90 countries. Camps are defined as bounded and fortified spaces housing minoritized populations subject to irregular detention, whom camp administrators purposefully neglect, often force into labor, and sometimes kill in large numbers. The construction of the datasets will be based on systematic coding of information from a diverse range of sources. The first dataset will include details of the approximately 150 systems of concentration camps. The second dataset will then catalogue details of the thousands of individual camps of which these systems are collectively comprised. These datasets will advance understanding of concentration camps by enabling quantitative research and facilitating comparison of historical and modern cases. The datasets will therefore significantly advance scientific understanding of the causes, conduct, and consequences of concentration camps as well comparative patterns of mass detention inside and outside of war. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.