After being inactivated there on 6 February 1945, it was redesignated HHT, 310th Cavalry Group, Mechanized in the Organized Reserves on 23 December 1946 before being activated on 20 January 1947 at Los Angeles.
It was originally constituted on 5 August 1917 during World War I in the National Army as the headquarters of the 179th Infantry Brigade of the 90th Division.
Organized at Camp Travis, the brigade was sent to France with the 90th Division as part of the American Expeditionary Forces, fighting in the Battle of Saint-Mihiel, the Meuse-Argonne Offensive, and the Lorraine Campaign.
[3] After the United States entered World War II, the company was converted into the 90th Reconnaissance Troop, without 3rd Platoon, on 30 January 1942.
The 310th ACR did not inherit the lineage of the prewar 310th Cavalry Regiment, and was not authorized a coat of arms or distinctive unit insignia.