The US homeland is the physical region that includes the continental United States, Alaska, Hawaii, US territories, and surrounding territorial waters and airspace. The homeland is a functioning theater of operations, and the Department of Defense (DOD) regularly performs a wide range of defense operations within the theater. DOD is responsible for the homeland defense (HD) mission, and leads the response with support from international partners and United States Government (USG) departments and agencies. The homeland operational environments require pre-event and ongoing coordination with interagency and multinational partners to integrate capabilities and facilitate unified action. DOD plans and prepares to operate in concert with other USG entities. HD, defense support to civil authorities (DSCA), and homeland security (HS) operations or events may occur simultaneously. The Department of Homeland Security is the lead federal agency for HS. HS is a concerted national effort to prevent terrorist attacks within the US; reduce domestic vulnerability to terrorism, major disasters, and other emergencies; and minimize the damage and recover from attacks, major disasters, and other emergencies that occur. DSCA is support provided by US federal military forces, DOD civilians, DOD contract personnel, DOD component assets, and National Guard (NG) forces in response to requests for assistance from civil authorities for domestic emergencies, law enforcement (LE) support, and other domestic activities, or from qualifying entities for special events.