Homeland security or Homeland defense is a neologism referring to domestic governmental actions justified, or allegedly justified, by potential guerrilla attacks or terrorism. The term became prominent in the United States following the September 11, 2001 Terrorist Attack, although it was used less frequently before that incident.

Such domestic governmental actions include:

• Emergency mobilization, including volunteer medical, police, and fire personnel
• New domestic surveillance and spying efforts, particularly with respect to immigration, transportation, military installations, and utilities
• Secret arrests and detentions
• Infrastructure protection
• Border control

In the United States, the concept of homeland security extends and recombines responsibilities of much of the executive branch, including FBI, National Guard, Immigration and Naturalization Service (INS), United States Customs Service (now the United States Customs and Border Protection Service), Secret Service, Department of Justice, and the Central Intelligence Agency. The George W. Bush administration has consolidated these and many other such activities, formerly in separate Executive Departments, under the United States Department of Homeland Security, a new Executive Department created for these purposes.

See also

• Civil defense
• USA PATRIOT Act
• United States Department of Homeland Security
• Tom Ridge