Daily AncestorC-File
A C-File is a federal certificate file holding the government's copies of a person's naturalization papers, kept for citizenship granted from 1906 to 1956.
The 1906 law made every naturalization court send copies of declarations, petitions and certificates to Washington, where they were filed by certificate number. C-Files also cover derivative citizenship and repatriation, which may never appear in a court record.
A C-File can be more than copies: a case reopened for a lost certificate or a pension claim may hold extra forms and letters. Files from 1906 to about 1944 survive mainly on microfilm. USCIS holds them and answers requests through its Genealogy Program.
How to cite this page
Daily Ancestor. "C-File." Dictionary of Old Record Words. https://dailyancestor.com/dictionary/immigration/c-file. Last checked 2026-10-03.