Dear Mr. Thomas,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located Letters Received, 1805 - 1889 in the Records of the Adjutant General's Office, 1762 - 1917 (Record Group 94) that may include the correspondence you seek. Portions of the series have been digitized and are available online, but not all records in this series are available online using the Catalog. The series is indexed by Indexes to Letters Received, 1812 - 1889 in Record Group 94, which is not available online. For assistance in locating specific letters, please contact the National Archives at Washington, DC - Textual Reference (RDT1) at Archives1reference@nara.gov.
Additionally, if the maps were filed separately from the letters, they may be in the custody of the National Archives at College Park - Cartographic (RDSC). Their email address is firstname.lastname@example.org.
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 RDT1 and RDSC. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this is helpful. Best of luck with your research!