Why Request a USCIS C-File?

A researcher sent the USCIS Genealogy Notebook a very important question:

What is the difference between a search requested from the National Archives (ordering reproductions, Immigration & Naturalization Records) and requesting information from USCIS? Does the content from these two sources overlap? Thank you for your help in understanding the difference between what is available from each agency for Naturalization records.

The question is important because it speaks to the most common misconception about USCIS historical records, namely that USCIS C-files are exact duplicates of court records. Yet C-Files are not exact duplicates of court records for three reasons:

1. Technically, the duplication is not exact because C-Files contain a copy of the naturalization certificate issued to the new citizen in addition to duplicate court forms. That said, if the C-File contains only a certificate, petition for naturalization, and declaration of intention, researchers might consider that C-File as little more than a duplicate of court records available from the National Archives (NARA) or from a courthouse.

2. Not all C-Files are small. Millions of C-Files contain a variety of additional forms and documents generated before or after the naturalization date. To see some examples visit the C-Files Image Gallery.

3. Many C-Files relate to citizenship, not naturalization, and so contain no court records at all. For example, minor children listed on a father’s petition could later apply for their own certificate of citizenship, creating a derivative C-File. Read more about Naturalization Records Not Duplicated in Court Records, or review our table of Certificate Series showing the series-specific numbering.


Records National Archives USCIS
Federal Court naturalization records 1790-1906 Original records (Record Group 21) N/A
State and local court naturalization records 1790-1906 N/A* N/A
Federal Court naturalization records 1906-1956 Original records (Record Group 21) Duplicate copies of court records and any additional records created in the case. See C-Files
State and local naturalization court records 1906-1956 N/A Duplicate copies of court records and any additional records created in the case. See C-Files
All court naturalization records 1956-1992 Federal Courts only, Original records (Record Group 21) Duplicate copies of all court records and any additional records created in the case filed in A-Files, See also the A-Files image gallery.

*The National Archives does hold occasional naturalization records or indexes from a state or local court. For example, the Index to New England Naturalization Records, 1791-1906 (PDF) refers to records in all courts in New England in those years. It is important to note this index is not a court record but a product of the US Immigration and Naturalization Service (NARA Record Group 85).

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