The U.S. Department of Homeland Security (DHS) is a Cabinet-level federal agency. It was established by the Homeland Security Act of 2002. The department's purpose is to protect United States territories from terrorist attacks and to respond to natural disasters.

On April 26 and April 27, 2009, Secretary Napolitano held a joint press conference with other Obama Administration officials to discuss the readiness of the Homeland Security department to respond to the swine flu outbreak. She indicated that the U.S. was prepared to respond to the outbreak as a full scale pandemic.CNN: WHO raises pandemic alert level... (April 27, 2009)

1. Federal Emergency Management Agency
2. Transportation and Security Administration
3. U.S. Immigration and Customs Enforcement Agency
4. US. Citizenship and Immigration Services Agency

1. September, 2001: President Bush announces the creation of the Office of Homeland Security (OHS) in response to the 9-11 terrorist attacks
2. November 25, 2002: The Homeland Security Act is passed, forming the Department of Homeland Security (DHS)
3. January 24, 2003: Tom Ridge named the Secretary of DHS, many OHS functions merged into DHS
4. March, 2003: All remaining OHS functions merged into DHS
5. November 30, 2004: Ridge resigns as Secretary
6. January 11, 2005: President Bush nominates Michael Chertoff as new Secretary
7. February 15, 2005: Chertoff confirmed as Secretary by a unanimous Senate vote
8. January 20, 2009: Janet Napolitano confirmed as Secretary by the U.S. Senate

A nine-page document was sent to police and sheriff's departments across the U.S. on April 7, 2009, titled "Rightwing Extremism: Current Economic and Political Climate Fueling Resurgence in Radicalization and Recruitment." The report was a warning to law enforcement to be on guard for "rightwing extremist activity" due to the recession, the first black president and disgruntled war veterans. Another report, "Domestic Extremism Lexicon", was retracted but defined groups who could pose a domestic threat.Washington Times: Federal Agency Warns of Radicals on Right (April 14, 2009)