On May 20, 1966, the 18th Military Police Brigade was activated at Fort Meade, Maryland. Members of the HHC deployed to Vung Tau, republic of Vietnam on September 7, 1966. On September 26, 1966, the Brigade assumed operational control over all non-division military police units in the republic of Vietnam.
The brigade was composed of three major subordinate elements: the 16th Military Police Group at Nha Trang, the 89th Military Police Group at long Binh, and the 8th Military Police Group (Criminal Investigation), also at long Binh. The 16th and 89th Military Police Groups were composed of seven Military Police Battalions containing a mixture of military police and infantry companies. The total strength of the Brigade numbered more than 5,000 personnel.