The new cabinet-level department created within the U.S. government after the September 11 attacks was the Department of Homeland Security (DHS). It was established by the Homeland Security Act of 2002 and began operations on March 1, 2003. The DHS was created to consolidate and coordinate efforts related to public security, including anti-terrorism, border security, immigration, customs, cybersecurity, and disaster prevention and management. This was the largest government reorganization in the U.S. since the Department of Defense was created in 1947, incorporating 22 agencies into a single department to address the new security challenges highlighted by the 9/11 attacks