United States Navy

The United States Navy (USN) is the maritimeservice 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 KriegsmarineU-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 projectingblue-water navy, current large deployments include the Western Pacific, the , and the Indian Ocean, and it is able to rapidly respond to regional crises, making it a frequent actor in US foreign and military policy.

The Navy is part of the Department of the Navy, alongside the coequal United States Marine Corps, and is headed by the secretary of the Navy. The chief of naval operations (CNO) is the most senior Navy officer serving in the Department of the Navy. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the Navy is the third largest of US military service branches. The Navy maintains 290 deployable combat vessels as of 2023, including the world's largest fleet of nuclear-powered ships, between 11 aircraft carriers and 70 submarines. The world's largest naval aviation force with 4,012 operational aircraft, combat fleets include 471 F/A-18E/F Super Hornets and 458 Sikorsky MH-60 Seahawk helicopters. The Navy operates the Ohio-class submarines, which are assigned 1,895 nuclear warheads, representing 51% of the US nuclear stockpile and 19% of the global nuclear stockpile.