U.S. Department of Homeland Security

The U.S. Department of Homeland Security (DHS) is an executive (cabinet-level) department of the United States government whose primary mission is to protect the security of the nation. It was formed in 2003 in response to the 9/11 attack, which, in terms of visibility, made counterterrorism its highest priority. Nevertheless, it did consolidate organizations with overlapping functions, especially in border security. It made a permanent home for some agencies that had been operating on an ad hoc basis, such as the Transportation Security Administration responsible for airline security. In other areas, such as national-level disaster response, it has not responded as well as in past situations where independent agencies handled incident response at the national level.

The Federal Emergency Management Agency (FEMA), which was previously an independent agency, became part of DHS. As a result of after-action review of the FEMA response to Hurricane Katrina, President George W. Bush signed the Post-Katrina Emergency Reform Act. This reorganized FEMA, and gave it more resources and responsibilities within DHS, becoming effective on December 31, 2007.

Formation and consolidations

While an Office of the Secretary was formed, most of DHS came from other government departments.

Pre-DHS (prior home)	In DHS
U.S. Customs Service (Department of the Treasury)	U.S. Immigration and Customs Enforcement - customs law enforcement responsibilities
	U.S. Immigration and Customs Enforcement - customs and visitor law enforcement responsibilities
U.S. Immigration and Naturalization Service	U.S. Customs and Border Protection - inspection functions and the U.S. Border Patrol
	U.S. Immigration and Customs Enforcement - immigration law enforcement: detention and removal, intelligence, and investigations
	U.S. Citizenship and Immigration Services - adjudications and benefits programs
Federal Protective Service	U.S. Immigration and Customs Enforcement
Transportation Security Administration (Department of Transportation)	Transportation Security Administration
Federal Law Enforcement Training Center (Department of the Treasury)	Federal Law Enforcement Training Center
Animal and Plant Health Inspection Service (part)(Department of Agriculture)	U.S. Customs and Border Protection - agricultural imports and entry inspections
Office for Domestic Preparedness (Department of Justice)	Responsibilities distributed within FEMA
Strategic National Stockpile and the National Disaster Medical System	Returned to Department of Health and Human Services, July, 2004
Nuclear Incident Response Team (Department of Energy)	Responsibilities distributed within FEMA
Domestic Emergency Support Teams (Department of Justice)	Responsibilities distributed within FEMA
National Domestic Preparedness Office (Federal Bureau of Investigation,Department of Justice)	Responsibilities distributed within FEMA
CBRN Countermeasures Programs (Department of Energy)	Science & Technology Directorate
Environmental Measurements Laboratory (Department of Energy)	Science & Technology Directorate
National BW Defense Analysis Center (Department of Defense)	Science & Technology Directorate
Plum Island Animal Disease Center (Department of Agriculture)	Science & Technology Directorate
Federal Computer Incident Response Center (General Services Administration)	US-CERT, Office of Cybersecurity and Communications in the National Programs and Preparedness Directorate
National Communications System (Department of Defense)	Office of Cybersecurity and Communications in the National Programs and Preparedness Directorate
National Infrastructure Protection Center (Federal Bureau of Investigation)	Dispersed throughout the department, including Office of Operations Coordination and Office of Infrastructure Protection
Energy Security and Assurance Program (Department of Energy)	Integrated into the Office of Infrastructure Protection
U.S. Coast Guard (Department of Transportation)	U.S. Coast Guard
U.S. Secret Service (Department of the Treasury)	U.S. Secret Service