USNORTHCOM was established on 25 April 2002 when President George W. Bush approved a new Unified Command Plan,[9][10] and attained initial operating capability on 1 October 2002.

[11] According to the UCP, Northern Command's mission is to:[12] USNORTHCOM's Area of Responsibility (AOR) includes air, land and sea approaches and encompasses the continental United States, Canada, Mexico and the surrounding water out to approximately 500 nautical miles (930 km).

[14] In May 2011, NORTHCOM was mobilized in the wake of the BP oil spill in the Gulf of Mexico[15] to provide air, ground, and logistical support.

[20] In its first period of organising in 2002–03, one priority was to hire civilian staff which could help respond to a Weapons of Mass Destruction attack and to coordinate disaster recovery.

The United States Coast Guard's 17th District works closely with ALCOM and de facto acts as its maritime component.

[35] The total of 14 agencies with representatives at NORTHCOM in December 2002 included the State Department, NASA, and the Federal Aviation Administration.

[38] The Posse Comitatus Act of 1878 and subsequent Department of Defense policy constrains any member of the United States Army, Air Force, Navy, or Marine Corps, and the National Guard under federal authority from domestically intervening in a law enforcement capacity on United States soil.