Central Office (CO) subject files (1957-1995)

NARA Record Group 84, Entry P-4A

(NARA ARC Identifier 1273013 / Local Identifier / MLR Number P 4A, P 4B )

Location: National Archives (NARA) Washington, DC [select records dating prior to 1975]; USCIS [records 1975-1995, requires FOIA request]

Finding Aid: Central Office Subject File Catalog (USCIS History Library)

In 1956 the INS implemented a new filing system designed to remedy many of the problems associated with 56,000 series. The new system, known as the Central Office or “CO” File System, gave all files the CO prefix and keyed the first 599 index numbers to related sections of Title 8 of the Code of Federal Regulations, Aliens and Nationality. For example, the files under CO 212.3 contain policy and correspondence concerning noncitizens excludable on medical grounds.  Files above 599 were given subject headings and cover all other aspects of INS’s administrative and operational functions. The CO File System houses only subject-related documents, as distinguished from individual case files, which were thereafter filed in each individual’s A-file. The CO File System also mandated that correspondence and policy documents be filed separately. 

Today, surviving CO files will be found in either RG 85, entry P-4A or still with USCIS.  Files in RG 85 generally date from 1957 to 1974. Unclassified files at NARA, processed and made available to researchers within the past two years, are stored in Washington, DC. Classified files with NARA are stored in the College Park facility and viewing them requires a request to the NARA FOIA office. Files still with USCIS date from 1957-1995, though coverage is better for years prior to the 1980s. Viewing CO files still with USCIS requires a request to the USCIS FOIA Program.

CO files are indexed by the Central Office Subject File Catalog, which lists the files numerically and alphabetically by subject.  The Catalog also references the corresponding 56,000 series file for subjects active prior to 1957. A copy of the Central Office Subject File Catalog is available to researchers in the USCIS History Office.  Researchers who need assistance determining the location of a particular file should contact the History Office for assistance.