Constituted 5 July 1918 in the National Army as the 1st Battalion, 40th Field Artillery and assigned to the 14th Division
Organized 10 August 1918 at Camp Custer, Michigan
Demobilized 6 February 1919 at Camp Custer
Reconstituted 1 October 1933 in the Regular Army
Activated 4 June 1941 at camp Roberts, California
Reorganized and redesignated 1 March 1943 as the 974th Field Artillery Battalion
Inactivated 10 January 1946 at Camp Patrick Henry, Virginia
Redesignated 5 February 1947 as the 509th Field Artillery battalion
Redesignated 25 June 1948 as the 509th Armored Field Artillery Battalion
Assigned 30 July 1948 to the 3d Armored Division and activated at Fort Knox, Kentucky
Relieved 1 October 1957 from the 3d Armored Division and inactivated in Germany with all personnel and Equipment being transferred to the 2d Field Artillery Battalion, 73d Artillery
Consolidated 16 September 1962 with the 40th Artillery
