The Army National Guard (ARNG) is an organized militia force and a federal military reserve force of the United States Army. It is simultaneously part of two different organizations: the Militia of the United States (consisting of the ARNG of each state, most territories, and the District of Columbia), as well as the federal ARNG, as part of the National Guard as a whole (which includes the Air National Guard). It is divided into subordinate units stationed in each state or insular area, responsible to their respective governors or other head-of-government.
The Guard's origins are usually traced to the city of Salem, Massachusetts, in 1636. That year a regiment of militia drilled for the first time to defend a multi-community area within what is now the United States.