Order of precedence in the United States

The United States order of precedence is an advisory document maintained by the Ceremonials Division of the Office of the Chief of Protocol of the United States which lists the ceremonial order, or relative preeminence, for domestic and foreign government officials (military and civilian) at diplomatic, ceremonial, and social events within the United States and abroad. The list is used to mitigate miscommunication and embarrassment in diplomacy, and offer a distinct and concrete spectrum of preeminence for ceremonies.

Source: Wikipedia — Order of precedence in the United States (CC BY-SA 4.0)