The United States Department of Homeland Security (DHS) is the U.S. federal executive department responsible for public security, roughly comparable to the interior, home, or public security ministries in other countries. Its missions involve anti-terrorism, civil defense, immigration and customs, border control, cybersecurity, transportation security, maritime security and sea rescue, and the mitigation of weapons of mass destruction. It began operations on March 1, 2003, after being formed as a result of the Homeland Security Act of 2002, enacted in response to the September 11 attacks.
https://en.wikipedia.org/wiki/United_States_Department_of_Homeland_Security