1977: NARA assigned Record Group 457 to declassified NSA records.
The National Security Agency had several predecessor agencies. Records generated or maintained by these predecessors are included in Record Group 457. For this reason, while the NSA was not established until 1952, it includes records of interest to those researching earlier periods. Many of the records in RG 457 were not created by the NSA/CSS. These records were generated by predecessor agencies, and maintained and used by the NSA/CSS.
Predecessor agencies whose records may be represented in Record Group 457 include subdivisions of the War Department, the Department of the Army, the Department of the Navy, the National Military Establishment, and the Department of Defense.
Other agencies that are heavily represented in RG 457 include the Signals Intelligence Service and its subdivisions, the Army Security Agency and its subdivisions, the Armed Forces Security Agency, subdivisions of the Office of Naval Intelligence, and the United States Air Force Security Service, among others.