Seeking 340th Field Artillery muster rolls/rosters

Dear Mr. Slack,

Thank you for posting your request on History Hub!

Copies of most of the monthly rosters from November 1912 - 1943 for Army units are in the custody of the National Archives at St. Louis, MO. The World War I rosters have been digitized and are available on FamilySearch at https://www.familysearch.org/search/catalog/3378445?availability=Family%20History%20Library. If you have difficulty accessing FamilySearch, please write to the National Archives at St. Louis, ATTN: RL-SL, P.O. Box 38757, St. Louis, MO 63138-0757 or via email at stl.archives@nara.gov.

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 RL-SL. We apologize for this inconvenience and appreciate your understanding and patience.

We hope this is helpful. Best of luck with your research!