https://en.wikipedia.org/wiki/United_States_Northern_Command
LEARN.
The command is tasked with providing military support for non-military authorities in the U.S., and protecting the territory and national interests of the United States within the continental United States, Puerto Rico, Canada, Mexico, The Bahamas, and the air, land and sea approaches to these areas. It is the U.S. military command which, if applicable, would be the primary defender against an invasion of the U.S.
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). It also includes the Gulf of Mexico, the Straits of Florida, portions of the Caribbean region to include The Bahamas, Puerto Rico, the U.S. Virgin Islands, the British Virgin Islands, Bermuda, and the Turks and Caicos Islands.
NORTHCOM operates extensive domestic intelligence operations which both share and receive information from local, state and federal law enforcement agencies. Employees of the Federal Bureau of Investigation, Central Intelligence Agency, National Security Agency, Defense Intelligence Agency, National Geospatial-Intelligence Agency, and other agencies maintain offices at NORTHCOM and receive daily intelligence briefings.
Glen David VanHerck is sworn in by chairman of the Joint Chiefs of Staff, General Mark A. Milley, as commander of NORAD and USNORTHCOM in a change of command ceremony on August 20, 2020.
https://en.wikipedia.org/wiki/Glen_D._VanHerck