United States Navy

The United States Navy (USN) is the maritime service branch of the United States Armed Forces and is designated as the navy of the United States in the Constitution. With 290 combat vessels, it is the world's second largest navy, behind the People's Liberation Army Navy, and by far the largest by displacement, at 4.5 million tons in 2021. It has the world's largest aircraft carrier fleet, with eleven in service, one undergoing trials, two new carriers under construction, and six other carriers planned as of 2024. The Navy is a part of the Department of Defense and is one of six armed forces and eight uniformed services of the United States.

The Navy originates from the Continental Navy, established in the American Revolutionary War. The Naval Act of 1794 provided for constructing six heavy frigates, the first ships of the Navy, in the prelude to the Barbary Wars. The American Civil War saw the blockade of the Confederacy and seizing control of its rivers. In World War II, the Navy was central in defeating the Imperial Japanese Navy in the Pacific War and Kriegsmarine U-boats in the Battle of the Atlantic, supplanting the Royal Navy as the world's largest navy. During the Cold War, the Navy, rivalled by the Soviet Navy, began providing nuclear deterrence via its ballistic missile submarines. The Navy was a major participant in the Korean and Vietnam Wars, and later the Gulf War, Yugoslav Wars and war on terror. A global power projecting blue-water navy, current large deployments include the Western Pacific, the Mediterranean, and the Indian Ocean, and it can and rapidly respond to regional crises, making it a frequent actor in US foreign and military policy.