 The unit was activated for service during World War II, the Berlin Crisis, and Operation Iraqi Freedom (OIF).The ancestral unit of the 490th Civil Affairs Battalion was constituted in the Army of the United States as the Headquarters and Headquarters Detachment, 90th Military Government Company (also known as the 90th Military Government in some documents) and activated 25 August 1945 at the Presidio of Monterey, California, just days after Japan's surrender.The Presidio of Monterrey served as the central mobilization and holding site for all Military Government and Civil Affairs forces from all branches of service (mainly US Navy and US Army) in response to the realization for a need to successfully manage the occupations of Europe and Japan for reconstruction.