The Human Terrain System (HTS) was a United States Army, Training and Doctrine Command (TRADOC) support program employing personnel from the social science disciplines – such as anthropology, sociology, political science, regional studies, and linguistics – to provide military commanders and staff with an understanding of the local population (i.e. the "human terrain") in the regions in which they are deployed. The program evolved into a mechanism for supporting security force assistance. The program ended operations on 30 September 2014.