Overview#United States Federal Executive Departments are among the oldest primary units of the United States Executive Branch of the United States federal government of the United States—the Departments of State, War, and the Treasury all having been established within a few weeks of each other in 1789.
United States Federal Executive Department are analogous to ministries common in parliamentary or semi-presidential systems but, with the United States being a presidential system, their heads otherwise equivalent to ministers, do not form a government (in a parliamentary sense) nor are they led by a head of government separate from the head of state.
The heads of the United States Federal Executive Departments, known as secretaries of their respective department, form the traditional Cabinet of the United States, an executive organ that serves at the disposal of the president and normally acts as an advisory body to the presidency.
Since 1792, by statutory specification, the cabinet constituted a line of succession to the presidency, after the Speaker of the House and the president pro tempore of the Senate, in the event of a vacancy in both the presidency and the vice presidency. The Constitution refers to these officials when it authorizes the President, in Article II, section 2, to "require the Opinion, in writing, of the principal Officer in each of the executive Departments, upon any Subject relating to the Duties of their respective Offices." In brief, they and their organizations are the administrative arms of the President.