The Secretary of Homeland Security leads the third largest Department of the U.S. government, with a workforce of 229,000 employees and 22 components including TSA, Customs and Border Protection, Immigration and Customs Enforcement, U.S. Citizenship and Immigration Services, FEMA, the Coast Guard, Secret Service, Federal Law Enforcement Training Centers, the National Protection and Programs Directorate, and the Science and Technology Directorate.
Under the Secretary's leadership, DHS is responsible for counterterrorism, cybersecurity, aviation security, border security, port security, maritime security, administration and enforcement of our immigration laws, protection of our national leaders, protection of critical infrastructure, cybersecurity, detection of and protection against chemical, biological and nuclear threats to the homeland, and response to disasters.
Kirstjen M. Nielsen was sworn-in as the sixth Secretary of Homeland Security on December 6, 2017. Secretary Nielsen is the first former Department of Homeland Security (DHS) employee to become the secretary.