The Department of Homeland Security (DHS) was established by consolidating 22 different federal departments and agencies into a single, unified organization in response to the 9/11 attacks. Here are those original entities that were integrated into the DHS:

  1. U.S. Customs Service (from the Department of the Treasury)
  2. Immigration and Naturalization Service (INS) (from the Department of Justice)
  3. Federal Protective Service
  4. Transportation Security Administration (TSA)
  5. Federal Emergency Management Agency (FEMA)
  6. U.S. Coast Guard (from the Department of Transportation)
  7. U.S. Secret Service (from the Department of the Treasury)
  8. Animal and Plant Health Inspection Service (part of it related to border inspections, from the Department of Agriculture)
  9. Office for Domestic Preparedness (from the Department of Justice)
  10. Federal Computer Incident Response Center (from the General Services Administration)
  11. National Communications System (from the Department of Defense)
  12. U.S. National Infrastructure Protection Center (from the FBI/Department of Justice)
  13. Energy Security and Assurance Program (from the Department of Energy)
  14. Strategic National Stockpile and the National Disaster Medical System (from the Department of Health and Human Services)
  15. Nuclear Incident Response Team (from the Department of Energy)
  16. Domestic Emergency Support Teams (from the Department of Justice)
  17. National Domestic Preparedness Office (from the FBI/Department of Justice)
  18. CBRN Countermeasures Programs (from the Department of Energy)
  19. Environmental Measurements Laboratory (from the Department of Energy)
  20. National BW Defense Analysis Center (from the Department of Defense)
  21. Plum Island Animal Disease Center (from the Department of Agriculture)
  22. Federal Law Enforcement Training Center (from the Department of the Treasury)

It’s important to note that while these entities were consolidated under the umbrella of the DHS, many of them retained their unique missions and operational independence. Over time, some have undergone further reorganization or renaming within the DHS structure.