The Defense Security Service (DSS) is a federal agency of the United States Department of Defense that provides security and counterintelligence services to protect the nation's technological base and the classified information that is critical to the nation's defense. The agency was established in 1999 and is headquartered in Quantico, Virginia. DSS is responsible for conducting background investigations and security clearance adjudications for the Department of Defense and other federal agencies, as well as providing security education and training to government and industry personnel. The agency also conducts industrial security oversight and compliance activities to ensure that contractors and other private sector entities that work with the Department of Defense are in compliance with security regulations and requirements.