Dear Mr. Johnson,
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We searched online and located the U.S. Army Center of Military History publication Air Defense Artillery. The publication indicates that the 48th Coast Artillery Battalion was formed on 22 January 1944 from elements of the 56th Coast Artillery Regiment that had been activated on 2 June 1941 at Fort Cronkhite near San Francisco, California.
We searched the National Archives Catalog and located World War II Operations Reports, 1940-1948 in the Records of the Adjutant General's Office, 1917-1981 (Record Group 407) which may contain after action reports and other records for 56th Coast Artillery Regiment, Harbor Defense of San Francisco, the 48th Coast Artillery Battalion, the 906th Field Artillery Battalion, and the 81 Infantry Division. We also located General Correspondence, 1941 - 3/1/1946 and and Orders, 12/11/1941 - 3/1/1946 in Records of U.S. Army Defense Commands (World War II), 1942 - 1946 (Record Group 499) that include records relating to Harbor Defenses of San Francisco. For more information about these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at email@example.com.
Additionally we located Battery Emplacement Books, 1902 - 1942 in the Records of U.S. Army Coast Artillery Districts and Defenses (Record Group 392) that were created by the Harbor Defense of San Francisco. Plus, we located Fortification Files, ca. 1913 - ca. 1944 that include records documenting the construction of fortifications and coast artillery batteries to defend the Golden Gate and San Francisco Bay. These records are in the custody of the National Archives at San Francisco (RW-SB) and may be contacted via email at firstname.lastname@example.org.
World War II Army Enlistment Records are in the custody of the National Archives at College Park - Electronic Records (RDE) and are available via AAD (Access to Archival Databases) on the National Archives website at: https://aad.archives.gov/aad/. Click on "World War II" under the category section. A list of the databases relating to WWII will appear and select the first database to search the WWII Army Enlistment Records. We performed a search and located an entry for Staff Sergeant William E. Johnson of the Coast Artillery Corps that may be a match for your father. If this is not the correct person, we recommend using the Advanced Search form to add additional information such as year and place of birth to help find the correct result. However, please note that there are gaps in the database and not all Army soldiers who served during World War II are included.
If you have not done so already, we suggest that you request a copy of his Official Military Personnel File (OMPF). OMPFs and individual medical reports for enlisted men of the U.S. Army who were separated from the service after October 1912 and prior to 1958 are in the custody of NARA's National Personnel Records Center in St. Louis. In many cases where personnel records were destroyed in the 1973 fire, proof of service can be provided from other records such as morning reports, payrolls, and military orders, and a certificate of military service will be issued. Please complete a GSA Standard Form 180 and mail it to NARA's National Personnel Records Center, (Military Personnel Records), 1 Archives Drive, St. Louis, MO 63138-1002. Next of kin may also use eVetRecs to request records. See eVetRecs Help for instructions. For more information see Official Military Personnel Files (OMPF), Archival Records Requests.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RDT2 and RW-SB. Also, the National Personnel Records Center is servicing only urgent requests related to homeless veterans, medical emergencies, and funerals which may be faxed to 314-801-0764. We thank you for your patience and look forward to resuming normal operations when the public health emergency has ended
We also searched the Ike Skelton Combined Arms Research Library Digital Library and located Operation Report, 81st Infantry Division, Operation on Peleliu Island, 23 Sept. - 27 Nov. 1944 that lists the 906 FA Bn [906th Field Artillery Battalion] as part of the 81st Division Artillery. We also located Participation in the Western Carolines and Central Philippines operations that include a couple of references to the 48th Coast Artillery Battalion.
We hope this information is helpful. Best of luck with your research!