Information included in Record Group 75 from the National Archives is as follows: Records of Predecessor Offices; Records of the Office of Indian Trade; Correspondence of the Superintendents; Records of Trading Posts; Records from the Office of the Secretary of War; Correspondence of the Office of Indian Affairs (Central Office) and Related Records; Records of the Alaska Division of the Bureau of Indian Affairs; and Records of Field Jurisdictions. The Bureau of Indian Affairs, usually known as the Office of Indian Affairs, was established as a separate agency within the War Department in 1824. Congress established the position of Commissioner of Indian Affairs in 1832. The Office of Indian Affairs was transferred in 1849 to the newly created Department of the Interior, where it has remained. In 1947 the Office of Indian Affairs was renamed the Bureau of Indian Affairs. Source: "American Indians, A Select Catalog of National Archives Microfilm Publications." I hope this helps to clarify 'Record Group 75' instead of creating more confusion. Barbara