The 89th Military Police Brigade was originally activated as a "group", roughly the size of a modern regiment. The 89th Military Police Group was constituted in the Regular Army on 19 February 1966 and activated on 15 March of that year in the Republic of Vietnam.The mission of the 89th Military Police Group was to provide general military police support for the III Corps and IV Corps Tactical Zones. The group stayed in Vietnam in support of the two corps' areas of operation. The Group received 15 of the 17 campaign streamers that could be earned for Vietnam service. With the removal of US forces from Vietnam, the organization was inactivated on 21 December 1971.