|Formed||30 April 1798|
|Headquarters||The Pentagon, Arlington County, Virginia, U.S.|
|Parent agency||U.S. Department of Defense|
|Military service branches|
The United States Department of the Navy (DoN) is one of the three military departments within the Department of Defense of the United States of America. It was established by an Act of Congress on 30 April 1798, at the urging of Secretary of War James McHenry, to provide a government organizational structure to the United States Navy (USN); since 1834, it has exercised jurisdiction over the U.S. Marine Corps (USMC) and, during wartime, the U.S. Coast Guard (USCG), though each remains an independent service branch. It is led by the Secretary of the Navy (SECNAV), a statutory civilian officer.
Department of the Navy was an executive department, whose secretary served on the president's cabinet, until 1949, when amendments to the National Security Act of 1947 established the Department of Defense as a unified department for all military services; the DoN, along with the Department of the Army and Department of the Air Force, became a component of the DoD subject to the authority, direction and control of the Secretary of Defense.
From 2001 to 2019, proposals to rename the Department of the Navy to the Department of the Navy and Marine Corps were introduced with wide support in the United States Congress, but failed due to the opposition of Senator and former U.S. Navy officer John McCain.
The Department of the Navy is headed by the Secretary of the Navy, also known as the SECNAV in naval jargon, who has the authority to conduct all of the affairs of the Department, subject to lawful authority, the Secretary of Defense, and the President. The Secretary of the Navy is appointed by the President with the advice and consent of the Senate. The Secretary is assisted by an Under Secretary of the Navy, four Assistant Secretaries of the Navy and a General Counsel of the Department of the Navy, who are also appointed by the President with the advice and consent of the Senate.
The highest-ranking military officers in the Department of the Navy are the Chief of Naval Operations and the Commandant of the Marine Corps, who are the principal military advisors to the Secretary of the Navy. They supervise their respective military services of the Department of the Navy, and in a separate capacity serve as members of the Joint Chiefs of Staff. They are assisted by a Vice Chief of Naval Operations and an Assistant Commandant of the Marine Corps.
The Department of the Navy comprises two uniformed services: the United States Navy and the United States Marine Corps (sometimes collectively called the "naval services" or "sea services").
The Department of the Navy consists of all elements of the United States Navy and the United States Marine Corps. According to Navy Regulations Section 0204-2, the term "Navy Department" refers only to the executive offices at the seat of government.
The Department of the Navy is composed of the following: