Alan P Proctor & Jason T Waleford 
Maintaining Homeland Security [PDF ebook] 

The U.S. Department of Homeland Security (DHS) became the nation’s 15th Cabinet department in January 2003. Twenty-two agencies with different missions, operations and cultures were consolidated and realigned into one organization with its primary mission being that of prevention, preparation for and response to catastrophes affectingour homeland, while facilitating legitimate travel and trade (Appendix C). DHS now employs over 208, 000 individuals who are located in every state and many foreign countries making it the third largest cabinet agency.