Department of Homeland Security
The Department of Homeland Security combined 22 different federal departments and agencies into a unified, integrated cabinet agency when it was established in 2002.
Eleven days after the September 11, 2001, terrorist attacks, Pennsylvania Governor Tom Ridge was appointed as the first Director of the Office of Homeland Security in the White House. The office oversaw and coordinated a comprehensive national strategy to safeguard the country against terrorism and respond to any future attacks.
With the passage of the Homeland Security Act by Congress in November 2002, the Department of Homeland Security formally came into being as a stand-alone, Cabinet-level department to further coordinate and unify national homeland security efforts, opening its doors on March 1, 2003.
The President proposes to create a new Department of Homeland Security, the most significant transformation of the U.S. government in over half-century by largely transforming and realigning the current confusing patchwork of government activities into a single department whose primary mission is to protect our homeland. The creation of a Department of Homeland Security is one more key step in the President’s national strategy for homeland security.
The following three directorates, created by the Homeland Security Act of 2002 were abolished by a July 2005 reorganization and their responsibilities transferred to other departmental components:
(Link: https://www.dhs.gov/creation-department-homeland-security)