Redesignated as the 2nd Battalion, 917th Coast Artillery Regiment (Antiaircraft) and organized in Virginia on 30 November 1929.
Allotted to the Regular Army, redesignated as the 2nd Battalion, 70th Coast Artillery Regiment (Antiaircraft) and activated at Fort Monroe, VA on 4 November 1939.
During World War II, the 70th Coast Artillery landed on Guadalcanal with the XIV Corps on 23 May 1943.
The Institute of Heraldry official records state that the regiment's distinctive unit insignia was originally approved for the 917th Coast Artillery Regiment on 7 August 1935.
Tim Aumiller's book lists deployments of battalions of the regiment as follows: Also: