The U.S. Department of Homeland Security (DHS) is a federal agency established in 2003 in response to the September 11 attacks. Its primary mission is to protect the United States from various threats, including terrorism, natural disasters, and cyberattacks. DHS oversees several key agencies, such as the Federal Emergency Management Agency (FEMA) and the Transportation Security Administration (TSA). DHS works to enhance the nation's security by coordinating efforts among federal, state, and local governments, as well as private sector partners. The department also focuses on immigration enforcement and border security, ensuring that the U.S. remains safe while facilitating lawful travel and trade.