The United States Navy (USN) is a branch of the United States armed forces responsible for conducting naval operations. Its stated mission is "to maintain, train and equip combat-ready Naval forces capable of winning wars, deterring aggression and maintaining freedom of the seas." The U.S. Navy currently has nearly 500,000 personnel on active duty or in the Navy Reserve and operates 278 ships in active service and more than 4,000 aircraft.
The U.S. Navy traces its origins to the Continental Navy
, which was established during the American Revolutionary War
disbanded in 1790. The United States Constitution
, though, provided the legal basis for a seaborne military force by giving Congress
the power "to provide and maintain a navy." Depredations against American shipping by Barbary Coast corsairs
spurred Congress to employ this power in 1794 by passing the Naval Act of 1794
ordering the construction and manning of six frigates
. The U.S. Navy came into international prominence in the 20th century, especially during World War II
. Operating in both the European and Pacific theaters
, it was a part of the conflict from the onset of American military involvement from the attack on Pearl Harbor
to Japan's official surrender
aboard the USS Missouri
. The U.S. Navy had a role in the subsequent Cold War
, in which it evolved into a nuclear deterrent and crisis response force while preparing for a possible global war with the Soviet Union
The 21st-century U.S. Navy maintains a sizeable presence in the world, deploying in such areas as East Asia, Southern Europe, and the Middle East. Its ability to project force onto the littoral regions of the world, engage in forward areas during peacetime, and rapidly respond to regional crises makes it an active player in American foreign and defence policy.