Dear Ms. Clayton,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located Records of Regiments Numbered 1 through 75, 1916 - 1934 in the Records of U.S. Regular Army Mobile Units (Record Group 391) that includes records of the 56th Artillery Regiment (Coast Artillery Corps). These records are arranged numerically by regiment, thereunder alphabetically by battery, and thereunder by type of record. We also located Records of Artillery Brigades, 1917 - 1919 in the Records of the American Expeditionary Forces (World War I) (Record Group 120) that includes records of the 31st Artillery Brigade, to which the 56th was assigned. Battery records may be part of the regimental records. For more information about these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
In addition, we located Photographs of American Military Activities, ca. 1918 - ca. 1981 in the Records of the Office of the Chief Signal Officer (Record Group 111), which contains two photographs of artillery pieces from the “56th C.A.C.” that may be the 56th Artillery Regiment (Coast Artillery Corps). These photographs have been digitized and may be viewed online through the Catalog. For more information about the records and to request a search for additional photographs, please email the National Archives at College Park - Still Pictures (RDSS) at email@example.com.
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 RDSS. We apologize for this inconvenience and appreciate your understanding and patience.
We also searched online and located the following information regarding the 56th Artillery Regiment (Coast Artillery Corps) and/or the 31st Artillery Brigade.
We hope this is helpful. Best of luck with your research!