The United States Department of Homeland Security (DHS) is an American federal executive cabinet-level department that handles public security-related matters, including counter-terrorism, border security, cybersecurity, immigration and customs, and disaster prevention, preparedness, and management. The DHS is headed by the Secretary of Homeland Security and headquartered in Washington D.C.
The DHS was created by the Homeland Security Act of 2002, which was signed into law by President George W. Bush in response to the September 11, 2001 terrorist attacks that occurred 14 months earlier. Pre-existing federal agencies dealing with topics touching on homeland security, such as the Immigration and Naturalization Service, the Federal Emergency Management Agency, and the U.S. Coast Guard, were moved from their original federal departments and consolidated within the DHS.
See e.g.; Department of Homeland Security v. Regents of University of California, 591 U.S. (2020)
[Last updated in September of 2022 by the Wex Definitions Team]