This primary source comes from the Records of the U.S. Senate.
National Archives Identifier:
305454Full Citation: Map of the United States Showing the Military Divisions and Military Departments of; 1865; Records of the U.S. Senate, Record Group 46. [Online Version, https://www.docsteach.org/documents/document/map-of-the-united-states-showing-the-military-divisions-and-military-departments-of, May 4, 2024]