The images shown in this gallery are of typical documents found in C-Files and are for representative purposes only. Some data have been omitted due to privacy reasons. Documents availability vary by case.
Naturalization Certificate Files (C-Files) opened for all naturalizations performed by a
Federal, State, Territorial, or local court within the United States from September 27,
1906 to March 31, 1956. C-Files are identified by the certificate number appearing on
the face of the Certificate of Naturalization.
Unlike court naturalization records identified by date or declaration or petition number,
USCIS C-Files can only be retrieved by use of the certificate number.
In addition to the certificate, all C-Files contain standard documents that are duplicates
of court naturalization records. These include the Petition for Naturalization and, if
required, the Declaration of Intention to become a US citizen.
The forms used changed over time. Earlier forms tend to be hand-written while later
forms were typed. Photos were not included until 1929.
The vast majority of USCIS C-files numbered below C-6500000 come from microfilm.
Image quality can vary widely. The most important factor determining the image
quality of records from microfilm is whether they must undergo processing in the
Freedom of Information/Privacy Act system.
Whether on microfilm or hard copy, petition and declaration documents in C-files are
duplicates of court records. Hard copy documents are often carbon copies and so
may present quality problems as well.
Some C-Files contain a variety of documents not found among court records. One
common form found in C-Files is an Application for a New Naturalization Paper in Lieu
of one Lost, Mutilated, or Destroyed. Such applications provide information subsequent
to naturalization and often tell of incidents in the immigrant’s life (fire, flood, theft, etc.).
Immigrants who had difficulty remembering when, where, or how they arrived may
have generated additional documents now in the C-File. Typical is a form for Request
for Certificate of Arrival, detailing their recollection of departure, traveling companions,
Some C-files include a copy of a certified abstract of information from their passenger
arrival record on Form 505, used to prepare a Certificate of Arrival for naturalization
C-Files can contain correspondence covering a variety of matters. Letters dated
before the naturalization usually concern discrepancies in the record or efforts to
meet naturalization requirements. Letters dated after the naturalization may relate to
a lost certificate, expatriation, or the citizenship status of the immigrant’s spouse or
If the immigrant was classified as an Enemy Alien during World War II, their C-File should include an application to be excepted from that classification for naturalization purposes. Other documents connected to their Enemy Alien status may be included as well.
C-Files for naturalizations after April 1, 1944 may include earlier records and files, such as Registry Files or Visa Files. All prior records were gathered at the time of naturalization and consolidated in the C-File.